The Origin, Phylogeny, and Systematics of Mexican Terrestrial Isopda (Crustacea Oniscoidea)

There has been a great need for a study of terrestrial isopode in general and those of Mexico in particular.

THE ORIGIN, PHYLOGENY , AND S YSTEMATI CS OF MEXICAN TERRESTRIAL I SOPODA (CRUST AC EA , ONISCOIDEA) by Stanley B. Mulaik A Dissertation Submitted to the Graduate Faculty in Partial F ulfillment of The Requirements for the Degree of Doctor of P hilosophy Department of Invertebrate Zoolo gy and E ntomology Approved: Chairman, Thesis Committee Dean, Graduate School ; I ' V Univer sity of Utah 1954 ACKNOWLEDGMENT S In addition to the individual s mentioned i n the Introduction who made material a vailable for this study, othe rs contributed n1uch to the c arrying out of thi s work. R. V My most sincere thanks go to Dr . Chamberlin for hi s kind encouragement in this and other studies and to his patience when progress was slow , and for his numerous suggestions for improving this manuscript. T o Dr . Don M . Re es who in numerous ways made progress possible, my thanks are likewise extended. Those who accepted the b urden of reading through this manuscript were Dr. Don M. R ees, Dr. Angus M . Woodbur y , Dr. Se ville F lowers, and Dr Jt r ederick R . Evans. Their suggestions, which resulted in the elimination of some ambiguity and the inclusion of m aterial which contributed toward greater clarity, are appre ciated. T he University of Utah Research F und made a vailable funds which eased the financial burden of several trips into Mexico for collecting additional material and for obt aining a clear er c oncept of the ecological a spect s of the isopod fauna . Pe rhaps the one individual who carried the greatest bur den in this study was my wife Dorothea . iii Through her numerous kind words of encouragement, her many patient re-readings of the manu s cript, this study was pushed to its conclusion. Likewise, her contributions to the collecting on field trips into Mexico were of considerable value . My sincere thanks likewise go to Allen Mulaik who aided in collecting of specimens on Mexican trips and who did much of the retyping of the manuscript in its early stages. iv T ABLE OF CONTENTS P age INTRODUCTI ON DISPOSITION OF MATERIAL f,TUDIED 3 TREAT:t.1ENT OF MATERI AL 4 HISTORICAL REVIEW 6 NOTES ON PHYLOGENY 18 ORIGIN OF MEXICAN ISOPOD5 23 BIOGEOGRAPHIC DISTRIBUTI ON 25 ECONOMI C IMPORTANCE 29 GENE RAL MORPHOLOGY 30 TAXONOMIC TREATMENT AND S YSTEMATICS 33 DISCUSSI ON AND CONCLUSI ONS 178 BRIEF BI BLIOGRAPHY 181 LIST OF FIGURES 188 V I NTRODUCTION There has b een a great need for a study of ter ~e strial isopods in gen eral and those of Mexico in particular , Ric hard son (1 905 ), la ck ing material from Mex i co , included only five s pe cies from t hat area in her monograph of the i sopods of N orth Ame rica . It was 1936 before anofoer comprehe n s iv e study of the se crustac e ans w as made , when Dr . Willard G . Van Name published his e xtens i ve m on o g raph ic work , "The American Land and Freshwater I s opod C r ustacea" , He li sted 254 species for all of the We stern Hem i sphe r e , including t h irteen for Mexico . Of t he 254 s pe cies , twenty - two w e r e known to occur a lso in E urope , A frica , and As i a . Many of t hese world - wide form s are so we ll establis hed t hat it i s difficult to dete rmine w he t her they are indigenous o r introduced . Am ong these w i dely distribut e d forms , some had representatives i n Mex ico . Mulaik (1 942 , 1 943 ) published two pape r s primar ily dealing with species fro m S outhwestern Unit ed States , of which twe l ve were new. The p r oximity of some of t he se t o the Mexican border prompt ed belief t hat most of them s h ou ld occur in t hat country. Howeve r , sinc e collections of t he s e crusta c eans a r e sti ll r e la tiv ely sparse , particularly in t he n or the rn t i er of Mexican states , few southern for m s of th e United States are known from across the border . 2 The paucity of t he k n o wl e dge of the Me xic an isop ods was rea liz e d w hen a l a r ge s e ries of colle ctions was sent to t he author for i de ntification , Thi s p a pe r i s t he r esult of s tudying a nd cl a s s i fying t he above mentione d m ate ria l a nd s ev e ra l add itional but s ma ller coll e c tion s , T he m at e rial ava ilabl e c ame largely fr on1 t he e xt e nsiv e colle ction s of Dr , F . B one t a n d hi s co - worke r s of t he Nat iona l S c h ool of Biolog ical Scie nce s i n Mexico City , D , F , A ddit ion al valuable m a - terial wa s se cur e d from t he c o lle ctions of t he Smith son i an Ins titu tion of Wa s hi ngton, D, C,, t he Ame rican M u s e u m of Nat u ral Hi s tory , a n d t he following in dividuals : D r . Cl a r e nce G ood n ight and h is wife , Mar i e , M r , Bor y s Malkin , Dr , Willi s J . Ge rt s ch , a n d t he aut h o r , DISPOSITION OF MATERIAL STUDH;D The g r eat e r portion of the specimens ma de availabl e for this study was r e c e ived from Dr . F . Bonet. Holotypes , allotypes and t he majority of the paratypes from t his m aterial will b e returned to the National S chool of Biological S ciences , Me xico City , D. F , Duplicat es of paratype s will be retained in t he colle ction of the Univ ers ity of Utah Invertebrate Museum . All of the material received from t he N ationa l Museum will b e returne d to t hat ins titution . Material r e c e ived from Dr . Clarenc e Goodnight , B o rys Malkin , and specimens colle cted by the author are deposited in the University of Utah Collecti on. Specimens received from the American Mu seum of Natur al History likewise will be returned e xcept in t he cas e s where there are duplicate s . 3 T R EATM E NT OF MAT 8 RIAL In the pr esent study of the terr est rial isopods of Mexi co, the descriptions of th e known fo r ms and of t h e new species wh ich have been id entified have been kept as brief and con cis e as i s consistent with clarity. In some inst anc es , more d rawings rather than e xt ended d e scriptions were used to give a cleare r concept of form and s t ructural detail. Sin ce the isopods do not h av e great ranges in siz e , the drawi ngs show structural details rather t han com pa rat ive d imensions , and a ccor d i ngly the size of t he drawing was determined primarily by the part icula r detail to be represented . The maj ority of the descriptions a.nd drawings in this study are original , except where indicated . In the need fo r econom y of space, e xplana tions of the figures in the plates have been kept at a m i nimum . In t he des criptions of the different species of isopods , consis t en cy was sought . Among the different genera , h owever , structu res var i ed in their t axonomic value , and treatment of t h e different species is not a lways uniform . Sinc e drawings show structures more accurately t han words , m o s t sp e cies hav e been illustr a t ed wit h on e o r m or e figures . ·where a single or few specim e ns were available , the whol e animal was p res erved as far as po s sibl e ; but in some instances it was consid ered 4 5 necessary to diss ect t he organism in or der to obtain a great er clarity of chara cters , and for this pur p os e the mout h parts , ple opods , and other structures were removed and mount ed in Hoyer 1 s m ounting media . ffiS T OR ICAL R E VI:2::W While worke rs in isopodology have b e en nume rou s , a g e n eral survey of the fi eld r e ve als that m any p e rplexing problem s still r ema in . A brie f revie w of the lit e ratur e s h ows the n ee d for a vig orous attack on the probl e ms of phylogeny wh i c h is still in confusion . A pproxim at e ly two t h ousand s pe cies of t e rrestrial isopods ha v e be en d e scribed , a nd most oft em are qui t e cl e arly s eg r egate d into gen e ra and fa m ilie s , Howe ve r, the r e i s lit tle c onsistency in t he lit e ratu re r egarding t he p lacement of famili e s in h i ghe r c ateg ories , and consid e ration s of p hylo genetic r e lations h ips ha ve not bee n cle arly outline d , The re ar e s e v e ral reasons for this . F irst , t he terr e stria l isopods of today are belie v ed to b e r emna n t s of e xte nsive ance stral popu lations wh ich orig inat ed through s e v e ra l line s of eme r genc e from a n aquatic habitat. Consequently , t he t e rr e stria l i s op od a compri s ing the, subord e r Oniscoid ea i s prob ably polyphyle tic w it h conve r genc e of s eve r a l basic c ha ract e ristics , A cl e a rer pictu r e of t he o r i g ins and t he p r e s ent - day p hyle tic r e lationshi ps has b een the obje ctiv e of nume r ous worke r s in t a xon om y , b ut t he fu n d amental basis fo r es t a bli shing a tr ust wo r t hy p hylogeny still a wa it s futu r e work e r s , 6 Secon d , t he r e i s a g r eat 7 need of work on comparative anatomy , embryology, serology, and related fields to gain an insight into the phylogenetic pattern. To date only a few workers have made studies of some organs and structures in several families , Jackson (1 928 ) reported t he results of his study of the morphology of the isopod head , Verhoeff (1917a, 1917b, 1920 ) carried out several studies on limited morphological characters and was able to clarify several generic and family relationships , No signi• ficant world - wide study of any major family has been made in order to lay the groundwork for a better phylogenetic under standing of isopods , Perhaps the most complete resume of the phylogenetic relationships was made by Vandel (1 943 ), fossil records of th e isopods , Third , there has been little work done on There have been only about fifty species of isopods described from fossil deposits . Practically all of these came from strata since the Carboniferous epoch; and most of them were of ,suborders of the lsopoda other t han the Oniscoidea. However, one of the most remarkable and significant Oniscoid species came from the Devonian deposits of Ireland which dat es these forms as very old. None have been reported from Mexico , perhaps because of insuffici ent inves tigation of fossil deposits . The order lsopoda was established by Latreille in 1817 in the first edition of Cuvier ' s " Regn e Animale" . In the second edition of this work published in 1829 , Latreille divided the order into six suborders , 8 including the aquatic and terrestrial forms , and this became a class ical standard for m any years . Since only the terrestrial forms in the suborder Oniscoidea will be considere d in the present paper, further discussion will be limited to this gr oup . In 1833, Brandt classified th e Oniscoidea as follows : TRIBES Groups Families Ligiea Porce llionea Oniscinea A rmadillina He xarthrica Schizarthrica A nnadillinia Cubar idea This classificati on was based on errone ous premises . T he He xarth rica , wh ich today comp ris e the genera, Tric h on i scus and Platyarth rus , im plies the possession of six segments i n the antennae . This would mean t he presence of only one article in the flagellum , when there are actually two . In 1844 , C. L . Koc h classified the suborder as follows : F a milies and genera Armadeillid ae 9 Pentheus (: Armadillo B r andt 1833 ) Armad illo ( • A rmadillidium Brandt 1833 ) Oniacidae It ea n . gen. P orc e llio Oniscus Ligiidae Ligia Zia n . gen • .Pherusa n . gen. No att empt was made to fit this classification to the h i gher h ie rarch ies crea ted by Brandt . M ilne - .8 dwards , in 1840 , in his fine work on t he crustac ea. , followed es se n t ially t he earlier classifica tion of Brandt . Later , in 1855 , Budde - Lund , in h is classical work on t he t e rres t rial isopods , pr e s ent ed t he following classification : Families l. Se ctions Oniscii Armadilloidea Oniscoidea 2. Li g ia e 3, Tylidae 4. Syspasti 10 Thi s classifi cation did not constitut e any great c hange . Por c ellionea was n ow Oniscoid ea . Many new genera and new species wer e added , and this work is considered to be the greatest step in bringing the t erre strial isopods to the front in the study of arthropods . It stimulated many workers to present papers on new species, d i stri butional records , local li s ts, anatomical studies , and several new families . The next compre hensiv e work appeared in 1905 when R ichardson published A m onog raph of the isopods of North Ame rica . I n t h is work the suborder On i s c oidea is divided into seven fa m ilie s : Tylidae , Oniscidae , A rmadillidiidae, Ligiidae , E ubelidae , S cypha cidae , and Trich oniscidae . In he r m onog raph , forty - one species are described in the Unit ed State s , while only five species were r eco rded for Me xico . T he phylogenetic relations were not discuss ed. The reason for adopting the particular fam ily arrangement was not enla r ged upon and the rela tionships can be gat hered only from t he s ynoptic key . In 1 917 Verhoeff published a new system of classification r e - sulting from the ch anged ideas regarding the group based u pon t he many new spe cie s r e c ently added and upon the new knowledge he h a d gained from extensive studies on t he r espiratory and other organs in these animals . His classification was es s entia lly as follows : 11 Families Superfamilies Hypotracheata Tylidae, Syspastidae , Stenoniscidae Atracheata Ligiidae , Trichoniscidae P l eu rotrach eata Oniscidae , P orcellionidae , A r madillida e , A rmadillidiidae , E ubelidae This classification d id not recogni ze the S cyphacidae , cr eat ed by Dana in 185Z and u sed by R ichardson in 190 5, and it synonymized the Cubaridae with the Armadillida e . The ne xt major work which was confined to the terrestrial isopods of the Wes tern Hemisphere was published by Van Name in 1936. In this monographic work thirte e n species for Mexico were included , These were includ ed in s e ven families, as did R ichardson, without con sidering those found e lsewhere . However , he suppr e ss e d the fa m ily Eubelidae , placing the gene ra formerly included in it in the family Cubaridae (: Armadillidae) , wh ic h was in turn cr eat ed from a portion of t he Armadillidiida e . Van Name followed the classification of Verhoeff and plac ed th e families of Ligiidae and Trichoniscidae in the superfamily Atracheata; the Scyphacidae , Oniscidae , A rmadillidiidae and Cubaridae in the Pleurotracheata, and the Tylidae in the Hypotracheata , In 1938 Verhoeff published t he results of d e tailed studies of t he 12 male genital structures and m odified h is classification of 1917 radically . He divid ed thirteen families into four tribes and placed five additional families of uncertain relationship separately. His classification was essentially as follows : Tribes I. Sections Pr otophora archaica Families Ligiidae Mesoniscidae ll. P rotophora derivata Hypotracheata Tylidae Syspastidae Stereosomata lll. E ndoph ora Stenonis cidae Trichoniscidae Buddelundiellidae IV. Embolophora Oniscidae Tendrosphaeridae P orcellionidae A rmadillidiidae Eube lidae A rmadillidae (Uncertain tribal relationship ) Titaniidae Schobliidae Bisilvestridae 13 Delatorr e ida e Cylindron is cidae In 1943 Vand e l published the results of a st udy of t h e phylogeny of t he isopods , His classification is presented in t he following t able in the two series h e created: Series Tylienne Hypot ra c heata Verhoeff 1 9 17 Tylidae Milne - E dwards 1840 Stereosomata Verhoef! 1 928 Stenoniscidae Verh oeff 1908 Se rie s Ligienne Pr otoniscoidea ( : P rotoph ora archai ca Verhoeff , 1936) L igiida e Brandt 1833 Mes oniscidae Verhoeff 1908 Euoniscoid ea E ndophora Verhoeff 1936 Trich oniscidae Sars 1899 Budde lundie llidae Verhoeff 1930 .Smboloph ora Verhoeff 1936 Scyphacida e Dana 1852 On iecida e Verhoeff 1 917 14 Porcellionidae Verhoeff 191 7 Tendosphaeridae Verhoeff 1930 A rmadillidiida e Brandt 1833 Eubelidae Budde - Lund 1899 Armadillidae Verhoeff 1 926 (: Cubaridae Brandt 1833 ) The five families of uncertain relationship which Verhoeff had included were omitted by Vandel as being ex:otic and n ot immediately pertinent to his study of the Terrestrial Isopoda of F rance , Several years later , Vandel (1945) modified his previous classification, abandoning parts of Ver h oeff 1 s classification . In a study of the Trichoniscidae he had found that the genital apophysis is not cover ed by the endopodites of the first pair of pleopods, but that the endopodites are themselves covered, incorr e ct and was reje cted. The term E ndophora was thus In the light of this , the term Embolophora is applicable to the Trichoniscidae only and not to the higher Oniscida e , thus it was like wise rejected , As a substitute , he used the terms founded on the fact that th e deferens canals are either fused or are separate at the anterior of the genital apophysis . He substituted t he terms pr oposed by Legrand , Synocheta for Endophora , and Crinocheta for E mbolophora . This necessitated a re - eva luation of the families . He elevated the sub - family Olibrinae to the rank of a family , which he placed close to the 15 S cyphacidae because of the nature of the mouth parts, m ulti - articulate flagellum , and other characters . This removed the Olibrinae from near the Ligiidae . The Stenoniscidae , which had been pla c ed in the Tylienne series , was mov ed to the Crinocheta on the basis of the type of genital structures , The family Delatorreidae was shown to belong to the E ubelidae , which were distinct from the Armadillidae on ge ographical and m o rphologi c al evidence , The Schobliidae , Titaniidae , Patagon - iscidae , Buddelundiellidae , and Trichoniscidae were placed in the compl ex Trichoniecoidea , Vandel 1 s 1945 organization of the families is as follows : I. Se ries Tylienne Tribe Hypotracheata Family Tylidae II. Se ries Ligienne Tribe Protoniscoidea Families Ligiidae , Me soniscidae Tribe Euonis coid ea Superfamily Synocheta Fam ilies Trichoniscidae , Titaniidae , Schobliidae , and Buddelundiellidae Superfamily Cr inocheta 16 Non volvational forms Families Stenoniscidae , Olibrinidae , S cyphacidae , Oni scidae , and Porcellionidae Volvational forms Families T end osphaeridae , A rmadillidiidae Eubelidae and Armadillidae Families of Uncertain P l acement Bisilveatriidae and Cy lindroniscidae In 1942 Vandel had considered the Armadillidae and Arma - dillidiidae as closely related . However , a re - e x amination of the repre • s entatives of the two families showed the former possessing trachea in all five pairs of pleopods , while t he latter has them only in the first two. This , together with other characters , led him to change his ideas of the ir phylog enetic relations . He considered the Armad:illidae a m ore highly developed form and farther re m oved from the Oniscidae t h an are the Armadillidiidae . with Styloniscus . In 1952a he synonymized the genus P atag oniscus This later genus then became t he genotype for t he fam ily Styloniscidae to replace the Patagoniscidae . In the present paper I have considered that the genus Protrichonisc us also belongs in the fa,;,ily Styloniscidae rather t han in the Trichoniscidae . The families treated in this pape r are t he Tylidae , Ligiidae , Styloniscidae , Tricho - 17 niscidae , Stenoniscidae , Scyphacidae , Rhyscotidae , Squamife rida e , Oniscidae , P orcellionidae , Armadilli diidae , Eubelidae , and Armad illidae . NOT E S ON PHYLOG E NY The Tylidae apparently arose from the same stock as the aquatic Valviferae , and the remaining families appear to have ar is en from the marine Cirolanidae . In the majority of aquatic isopods , the multiarticulate flagellum of the second antennae appears to be the prim itive condition, whic h still persists in the Ligiidae . These m o re primitive forms hav e but recently left an aquatic habitat along the temperate and tropical shores of t he world . The flagellum of some of the Trichoniscidae has about six segments , while i n the m ore advanced Oni scida e , Porcellionidae , Armadillidiida e , and Armadillidae , which show the greatest adaptation to a terrestrial habitat, it has only two or thr ee segments . Another prominent chara cteristic of the Oniscidae of phylo genetic value is t he greatly reduced first antennae . This structure seem s to be related to the acquisition of a terre strial mode of life , since a somewhat comparable r eduction is a lso to be found i n those amphipods of the Talitridae which inhabit t he tidal zone , while marine representatives have no noticeable reduction in this structure . Tylidae , the first antennae consist of one segment . In the The Stenon i scidae possess a very small one p l aced close to the base of the second antennae 18 19 while the Ligiidae have a muc h large r first antennae e xtending beyond the head . The affin ity for water , or at least wet ar eas , which t his family possesses , is possibly a primitive c haract er . Vandel points out t hat perhaps the first antennae possesses a physiological activity associated with a n aquatic habitat, and their r eduction parallels t he evolution to a terr e strial h abitat . It is suspected t ha t the " sense org ans " in the antennae discovered by Leydig (1 8 55 - 78 ) and named 11 d 1 aesthetasces " are olfa ctory or chemical organs . The development of t he habit of rolling in to a ball o r sphe r e , resulting in t he prot e ction of soft underparts from rapid dessication, particula rly t he pleopods , is an advanced adaptation to a terrestrial life . The concomitant change in the u ropod s and t e lson are pr onounce d toward thi s end. T he Tylida.e are a l s o capabl e of rolling into a ball , but t hese ar e forms found in moist areas along t he oc ean tide lines . It is believed that the Tylidae have r eturned to t h i s type of habitat as a secondary development afte r an e xi s tenc e in drier regions and climates . The Armadillida e and A rmadillidiida e are best adapt ed to a true t er r estrial life . Repr esentati ves ar e found widely distributed in Lower Sono r a n areas which are typic ally desert in nature . In prac - tically all species in t he se famil i es , whe n the animal rolls up , th e pro t e ction a ga inst dessication afforded the soft e r u nd erparts , and particu larly the tra cheat e ple opods , is evi dently quite e ffe ctive . 20 The second antennae of Armadill ida e are e nclosed with in the ball, providing considerable protection to these structures , In the Armadillidiidae the second antennae are not enclosed as in the above - mentioned family, but rest in grooves , thus forming a smooth outline . This manner of antenna l protection appe ars to be a less advanced development . In the Armadillidae the development of a sulcus , or groove , along the lateral margin of the first thoracic segment into which some of the margins of the posterior aegments fit, is a further refinement for compactness when the ani.-nal rolls up . No such sulcus occurs in the A.rmadillidiidae . In most species the sessile eyes are set into the head in such a manner as to maintain a smooth surface in the rolled - up condition. In the aquatic , non - oniBcoid isopods, the mandibles have characteristic triturating processes . These are likewise present in the Tylidae , Ligiidae , Stenoniscidae, Trichoniscidae , Styloniscidae and Scyphacklae . In some of these the re are variously developed plumose bristles associated with the triturating structure . In the Oniscoidea , Porcellionidae , Armadillidiidae and A. rmadillidae , there is a suppression or obliteration of the triturating area and the p lumose bristles are greatly enlai-ged, The number of eyes seems to lend itself to phyloge netic con - 21 sideration in the cours e of assuming a terrestrial m od e of life . In the primitive aquatic forms t he eye masses may contain up to s everal hundred oce lli. In the L igiidae , which are still confined to the tid e lines of t he world , or at l ea st to wet habitat s , the number of ocelli i s lar ge , while in t he more terrestrial forms t here i s a great reduction in the number of oc e lli. In those species which have assumed a cave life , the ey es ar e inc on spicuous or absent . In the other terrestrial forms the maj ority of s pe cies may have one , two, or up to abou t twenty oc elli. The phylogeny of t he Oniscoidea is stilt unsettled . Whil e some feature s appe ar cl ea r , at l east on the family level, as ind icat ed above , little ha s be e n done on the gener ic l evel. The re lationships among t he gene ra in m o st cas es is poorly understood . A contribution may be forthcoming t hr ough the field of embryology , whic h to date has been practically untouched . The ph ylogenetic relationships of Mexican Oniscoidea will be made clearer on ly when they are studied as a part of a world - wide fauna, a task considerably beyond the scope of t he present paper . Vandel (1943) p oints out t hat several families , such as t he Cylindr on iscidae and Budde lundie llidae , c annot be related clearly to any other fam ily. This com es lar gely from a lack of detailed anatomical and embryolog ical studies . 22 F or a graphic view of the more probably re lationship s am ong the families of Mexican Oniscoidea, a family tr ee is g ive n below. The level above the base line i s a tentative assessment of the d egree of ad vanc ement, the more advanced forms be i ng p laced h i gher on the chart. Eube lidae A rmadillida e Porcellionidae Onis cida e Ligl.idae Terrestrial Valvifera Cirolanidae Mar ine Fam ily T ree of Me xican Terrestrial I s opoda ORIGIN OF MEXICAN ISOPODS The origin of the Isopods in Mexico is an enigma , of distribution are not clear . Their cente rs Vandel has poin t ed out hypothetical lines of distribution for some E;uropean forms , but no definite , overall pi c tur e can be drawn for those known for Mexico. A number of representa - tives are found in caves , particula r ly in the genera Protric honis cus , Cuevonis cus , and Trichorhina , T hese evidently have been isolated for long periods of tim e , perhaps since Creta ceous , There is no evidence of P leist oc ene gla ciation e xcept in a few of the h i ghest m ountains . Caves in general are n oted for their great uniformity of temperature and hu midity, and even during th e P l eiocene and Pleistoc ene periods the limits for adaptation to a cave life were quite narr ow, That these forms could have been brought into t he area by man in r ecent times is doubtful . In such an instance there would be t he burden of finding the place of origin of these forms known only from the Mexican reg ion, Before a cl ear picture of the Mexican lsopod fauna can be gained, considerable study must be made of t he fauna of Central and South Amer ica , The number of n ew records and species in various genera of Mexican l sopods p oints to the possibility that future intensive coll e cting will show the Western Hemisphere to be as rich in these cr·u s t aceans as is the 23 24 Med iterranean r egion , which has been considered by some to be the center of or i g i n of present - day isopods . Two hundred species for Mexico is considered not too great an estimate . The distribution of species in the Weste r n Hemisphere indicate s that t he se forms have long been isolated. The Isop oda ha ve n ot been found a s fos sils to any great e xt ent and n one has be en reported from Mexico. The earlies t known fossils of isopod s ca me from the Devonian of Ir e land . fossils in Mexico m i ght some day come t o light . It i s possibl e that i sopod Judg i ng from the ve ry scanty colle ction s of pr e s e nt day forms , the fossil forms may likewise have been neglected . The a ntiquity of various gr oups within the Isopoda is difficult to establish . Membe rs of t he L i g iida e and Trichoniscidae are known to live with t ermite s , an association wh ich is considered very ancient , while the more advanced fam ilies hav e r ep r e s entatives living with ants . Vande l , Van Na me , and Verhoeff hav e con s ide r ed the m odern Oniscoid ea to have had their centers of distribution i n t he Med ite r ranean region primarily on the evi dences afforded by t he existing collections . While the Mediterranean r eg ion is at present t he center of most intensive collecting , it is n ot n e c essar ily a c enter of or i g in . The numer ous new species disc overed in Mexico and the anticipation of finding others might indicate t hat at least for s ome families t his reg ion merit s c ons i deration as a p ossible center of orig in. BIOGEOGRAPHIC DISTRIBUTION The species of t errestrial isopods found in Mexico do not all have equal value for biogeographical interpretation. There are som e forms which are cos m opolitan by virtue of t hei r ea sy distribution by man. T h i s has l e d some zoologist s to infer t hat isopods have littl e value fo r biogeographic studies . However , an examin ation of t he sp e cies of Mexico reveals that t he homophiles are n ot num erous . The most cosmopolitan for m s ar e P orcellio l aevis , Porcellio scaber , ~ n orthus pruinosus and A r m adillidium vulgar e . - Thes e are believed t o be of E uropean orig in and are now found e xtensively over the g r e ate r portion of the e arth . Othe rs ar e cosmopolitan to a l esser d eg re e b ecause they are more critical in their demands for suitable c limatic conditions . Tempe ratur e evidently is an important factor , since many forms do not e stablish t hemsel ves at h igh er e levations in the m ounta ins or at higher latitudes . Others are not to be found in the dry , h ot des e rts . accompanying facto r is t he hum idity. An Mo st sp e cies of iaopods a r e unabl e to w ithstand dee sication of the ir habitat. Without doubt the littoral zone repr esents the pr im itive habitat of the s e animals . Mexican isopods confined to the littoral zone are Ligia , Tylos , A r m adilloniscus , a nd Sten oni s cus . The littoral habitat over muc h of the ea rth s ho ws a marked 25 Z6 similarity in a relatively high humidity and in temperature changes of no great magnitude . These , together with an ease of coastwise dispersal, rule out littoral species for biogeographic consideration. The endemic non - littoral species are of most interest for bio geography. The members of the genus Armadillo, Protrichoniscus , Philoscia , Trichonis c us , Cuevoniscus n . gen. , Rhyscotus , and Metepo northus are more numerous , and most of the species treated here are apparently indigenous to the c ountry. Members of Protrichoniscus , Cuevoniscus and some of a few other genera prefer cave habitats . The lack of body pigment in members of these genera together with the poorly developed , almost pigmentless , eyes , indicates a relatively long association with the cave habitat . Little work has been done on the faunal areas of Mexico for any group of animals . Smith (1949) made a brief study of the herpetofauna and poi nted out some relationships to the flora . Yivb (1943) discussed the major faunal areas with respect to human populatl.o:,i, growth . Rela - tively nothing has been done: for the arthropods , due primarily to insuf ficient collecting and the lack of study of known forms in terms of bio geography. In common with the other arthropods , the isopods have been given little attention with respect to faunal areas . The present study yielded a fairly large number of specimens and of species , but does not reveal sufficient evidence for delimiting biogeographic and faunal areas . Z7 Mexico is roughly divided from east to west into northern Nearctic and southern Neotropical areas . The Lower Sonoran of t he Wes tern United States extends eouthward along the highland plateau to near the region of Mexico City. Very little collecting has been done in this subregion except in t hat portion which encompasses the islands and the shores along the Gulf of Lower California. Separa ting the Lower Sonoran Subr egion of t he Nearct ic from the Neotropical Region for a greater portion of its s outhward extension is the Si erran,Subreg ion , which is confined to the high m ountain ranges . Reference to the map on the following page , showing the m ajor subregions of Mexico , will indicat e their relation to the whole country. .,., ~·------~---(-~\ ·- ,, \ I 1j I ' I \ '( :a ' MA,TOR BIOT:'" 1~ f.1-·BT-fr:C: I,JHS \ \ OF fc!EX I CO ' ' \ \ I /J \_ f· - ' i:ea.r'ctic rtet .i. on I . ~onoran Su1•rea10! 1 II . S i erran 2uhre~io n III. raliforn~ an ~ubre~lo n Neotropi cel HcGion IV . Pacifie S11hrdfio n v' . Ciuata ·1£.ln.;1 Subregio n VI 1' I \ I \ i I L V~ . At1nr.t ~ <'. ~-n'r . reL;j_nn ltri_fl~)tcd fpo '// :1 Eol:'nrt ~1r,1ith ( 1949) / ! ECONOMI C I MPORTANCE lsopods feed largely on organic detritis such as l eaves , grass , and other p lant tissues, a nd in t h is respe ct function i n the cycle of soil formation , At time s they reach g r eat concentrations i n certain a1·eas. This is particularly notic eable with the larger pigmented ubiquitous for ms such as Armadillidium vulgare, Metapon orthu s pruinosus , and Po rce llio laevis . These species have followed m a n as he pursued his a gr icultu r a l activities over the great er portion of the earth, They occasionally b e come numerous in gardens and greenhou s es , frequently feeding on e conom ically im po r tant p l ants , There is little in t h e literature regarding the relation of these animals to Mexican ec onomy , a l t h ough it is likely that t hey may be come destructive locally. Reference t o r ecent works on ec onomic entomology will g i ve effe ctive controls , 29 G E N E RAL MORPHOLOG Y F or t h e average worker , some information regarding the morphology of isopods follows , Only the morphology necessary for understanding the species d e scriptions will b e g iven. Terrestr ial isopods ar e gene rally small, only a few spe cies reaching t en m illimeters in l ength. M ost species are dorso-ventrally flatt e ned, although in some the body is conve x . While m ost for m s are r e lative ly s m ooth , some h ave bodies with simple tubercles , s m all knobs , or elongated spine s . The majority ar e not capable of rolling into a ball , a characteristic highly d e v e loped in t he Armadillidiidae and the A rmadillidae , The body is d i vided in to thre e e asily r e cognized regions : t he head , or c ephalon, followed by the t h orax or meso soma , a nd the abdomen, or metasoma . In t he primitive condition t he head consists of s e ven segment s . There are two pair s of antennae ; the first pair ie gene rally minute a n d attached m e dially near t he base of the second pair , There are fiv e s eg - ments in t he larger second antennae which are terminat ed by slender two , t hr ee , or in some spe cies , more s egment ed flage lla e . 30 31 The appendag e s of t h e m outh consist primarily of a pair of In mandibles , Urst and second maxillae , and a pair of m axillipeds , the families Tylidae , Ligiidae , Trichoniscidae , Scyphacidae , and St e noniscida e , the mandibles have a more or l e ss distinct molar area variously modified as a triturating surface . Distal to this is the lacinia mobilis which has one or m or e plum os e bristles , differing according to species , The first m axillae are biramous ; t he outer branch usually bears a series of teeth , while t he inner branch b e ars several plumose setae. There are t hre e setae in the more primitive forms and two in those considered to be more recent . The second maxillae are s hort , flatt ened structures without teeth and with a deep cl e ft to form an inne r and outer lobe. The maxilliped bears a palp which consists of thre e , or occas i onally four , s egment s in the primitive forms, and usually two segments in t he more advanced forms , Young individuals in t he marsupium s h ow six t h oracic segments , but a sevent h segment is added when t he first m olt takes place, pair of l eg s occur s per segment. One Careful e xamination s h ows some specific diffe rences in all of the legs, though in gene ral they are much alike . The first and seventh ar e t he most m odified , These modifications ar e most pronounced as se condary sexual characte rs , t he ma l e s usually showing more ext ensive development of spines , T he segments of the legs 32 are the basis , ie c hium , merus , carpus, propodus and dactylis , The abdomen consists of six segments . The first five bear pairs of biramous pleopods in t he form of plates , the inner being g il llike , The outer plates generally cover the inner ones , preventing too rapid dessication, In some forms , tracheate struct11res occur in two or more of the outer plates , The tracheae open along the median border by a single opening in some forms , but in others there is a series of openings . characters . fied , In the males the pleopods offer g ood specific In the Ligiidae only the first pair of pleopods become modi - In the other families the first two pair are modifi ed , In any in - stance , both the oute r and inner branches become considerably e longated , Between the first pair is an e longated "penis" at the tip of which are the openings of the sperm ducts , The sixth abdominal segment bears a pair of uropods which are variously m odified , In the more primitive forms the uropods consist of an elong at ed basal segment to which are attached an endopodite and an exopodite , These are conside rably modifi ed , es - pecially in those forms adapted to a dry , terrestrial life , as in the Armadillidiida e and the Armadillidae , The sixth segment to which t he uropods are attached is generally designated in isopod studies as the tels on. TAXONOMIC T R EATMENT AND SYSTE MATICS The tr eat ment of families , genera and species of the Mexican isopods in this study is conservative. Th e world - wide distribution of species within c e rtain genera imposes caution on forming new genera and subgenera unless a world - wide study of the related forms c an be m ade . The present study was limited ge ograph ically and precluded such an approach . Many genera u s ed by previous workers are poorly diagnosed and delimited , and t he status of c e rtain fam ilies is not too cle ar . The known isopods of Mexico can be s eg regated by the followin g key into thirteen famili es . of which three are new. These are compos ed of twenty - four genera , In t he se genera t here are s e venty spe cies , of which forty - two are treated as new species in this stu dy. fifteen species are g iv en i n the hypot hetica l li s t . In addition, These are forms which have been r e ported in border r eg ions of the Unite d State s and Central Me xico , Keys have likewis e been prepared for m o s t of the gene ra , Cau- tion must b e exe rcised in t heir use since they were p r e pared primarily on available mate rial which , for many s pe cie s , did n ot provide enough 33 34 specimens to establish limits of variation. Numerous additional species no doubt will be colle cted and t he use of these keys for identi fying them may lead to error of determination , Re ference to the drawings will be an aid and a supplement to t he keys . Key to the Families of Mexican Oniscoid ea l, Molar area represented by a triturating surface ; m axilla I with 3 penicils on the inner branch . • Z la , M olar area without a triturating surface , but with a plu mose br i stle which may be compounded; maxilla I with Z penicils on the inner branch , . • • • • • • . • , • 5 Z. First ant ennae with one segment . Epimera of thoracic segments 11 to VU set off by distinct sutures , Capable of rolling into a ball . , • • • • • , • , • , • TY LIDA E Za , F irst antennae with 3 segments . E pimera not distinctly set off from the dorsal plate , Not capable of rolling into a balL . • • • • • • • • • • • • • • • • • • 3 3, Flag ellum of antenna II with over 8 segments ; ocelli · numerous , over fifty . • • , , • • • • , • • LIGllDA E 3a , F lage llum of antennae 11 with 6 or fewer segments ; oc elli less than fifty . . . 4 4. R ight molar with a penicil 4a. R i ght m olar without ·a penicil • 5, The teleon completely fills the body outline behind the fifth abdominal segment. The uropods are not visible from above , being ent i re ly underneath the telson • , • STE NONISCIDA E Sa , The telson fills only part , if any , of the body outline behind the fifth abdominal segment, The uropods are • STYLONICIDAE TRICHONISCIDA E 35 readily visible from above and fill a n area b e twe en t h e telson and the posterior corners of the fift h abd omina l se gment 6 6. Se c ond pair of ant ennae with 4 article s in the fla gellum. Masti catory lobe of t he ma Killiped acute ly produced. Molar area r e presented by a low bas e w ith a tuft of s e ta e • • • • • • • • • • • • • SCYPHACIDA E 6a . Se c ond pa ir of antennae with 5, 3, or Z a rticles in t he flag e llum . Ma sticator y lobe of t he maxillip e d lar ge r , truncate , and extends almost to t he tip of the pa lp. Molar ar e a obsol ete a r,d replaced by a plumose , someti mes com pound bristle • • • • • • • • • • 7 7. Rear outline of t he a bdomen ext ended. in eKternal pla t e s of the pleopods •• 8 7a. With trach ea in the e xt e rnal plates of th e ple opods 8. Fr ontal plate of the he ad g reatly e xpanded in a bu lb • RHYSCO TIDA E 8a. F ront of head with out a bulbous expansion • 9. B ody covered with numerous prom inent , s cale - like bristles . • • • • • • • • • • • • • S Q UA MIF ERI DA £ 9a. Few if any large scale - like bristles 10 . Rear outline of the abdomen e xt ended; the uropods usually e longat e d . If capable of rolling u p (£ti ist~ ), then ur opods are not clos e ly includ ed in t he sphere. • • • • • PORCE LLI ONI DA E lOa. Rear outl ine of t he a bdomen m o re or l e ss circular ; t he uropods ar e s h ort; capabl e of rolling into a tight b a ll 11. With out trachea 10 9 • • • • ONI SCIOA E 11 The s pace b etween t he t e lson and the fift h abdominal segment is fill e d by the br oad r ectangular outer branch of the uropod , which is atta c hed to the basal portion by a broad suture. • • • • • • • •• •• ARMADILLIDII DA E 36 lla. The space between the telson and t he fifth abdominal segment is fifth otherwise. • • • • • • • • • • • • 12. Flagellum of antenna e II composed of three segments ; exopods set in the pos terior median corner of the basal piece of the uropod . Telson does not r e ac h the rear border of the animal • • • • • • , • • • • • EUB E LIDA E l Za . Flagellum of antennae 11 composed of two segment s . Exopod of the uropod s e t along the medial border of the basal piece , The telson is truncate and its rear border forms part of the body outline , , ARMADILLIDA .S 12 Descriptions of Species of Mexican Land lsopoda Subord e r ONISCOID SA This subo rder i ncludes all terrestrial, or land iaopods , although some species pre fer a moist habitat and can withstand lengthy immersion in salt water . The isopods in this group are characterized by having s e ven pair of legs modified for progression on land and by t h e reduction of the first antennae to small rudiments consisting usually of three seg ments , There is no palp or jointed appendage on the mandibles . The pleopods may be adapted for r e spiration in air . TYLIOAiL In this family t he eyes are quite large and are compos ed of numerous minute ocelli. The h e ad has a raised , s hield - like epistome . 37 A character distinguishing this family from the others is a distinct suture which separates off the epimera o{ the second to the seventh thoracic segments . Antennae I are minute and single segmented . Ant ennae II are stout and have a four - segmented flagellum . The mouthparts are of a primitive type . The mandible has a triturating molar with a number of setae arising from near its inner apex and a large number of penicils between the molar area and the setose pad near the apex . In both sexes the first pair o{ pleol?ods are rudimentary while pleopods two to five are normal , biramous with the outer branches provided with trachea . The basa l segment of the uropods are not visi - ble from above , and form an operculum over the anus . The outer branch is minute , the inner branch is absent . This group of i sopods is capable of rolling into a complete ball. Only a single genus , Tylos, is known. The members of this genus gen - erally occur at the ocean beaches and are primarily nocturnal , preferring to bury in damp sand during the day, The ability to roll into a ball, and the presence of trachea in the pleopods , together with other characters which are related to a terrestrial habitat , leads to the belief tha t these animals have secondarily returned to a moist tide - line habitat . 38 Tylos Latreille, 1829 The characters gi ven for th e family Tylidae lik e wise apply to the g enus Tylos , whic h is t he only g e nus in t he family . Numerous c hara cters are useful for d e termination of the species . Detailed dif - ferences in the mouthparts ; the g en e ral s h ape of the free epimera of th e thoracic segments two to seve n ; the nature of the dorsal armature of setae; and the outline of the front of the head which is scalloped to rece i ve the antennae when the animal rolls up , are all useful in the study of this group . Genotype : Tylos latreillei Adouin and Savigny, 1826. Key to the M exican Species of Tylos l. la. With a slightly concave posterior bor der of the t e ls on P osterior border of t he telson straight . latr e illei nive ua Tylos latreille i A douin and Savig.ny , 18 26 F igures 1 - 4 T h i s is a sp e cie s large r than Tylos n iv e us whic h may occur in the sam e re gion of Me xico. It me a sur e s a bout 17 mm. i n l en gt h . Th e dora u m is spars e ly cover ed with seta e . The blun t e r point of t he head r eg icn in front of the e y e s, t he slightly con ca ve r e ar part of t he 39 telson, and the different contour of the epimera of segment VI would distinguish it from T . niveus or from T , punctatus which may occur in Mexico. There are about 35 ocelli in each eye , Localities : Baja California , San Quintin Bay. Numerous specimens collected under stones by Menziea , Horvath and Re is h on April 6 , 1950 , T iburon Island; numerous specimens collected by the Albatr os Expedition on April 12 , 1911 . Sonora , Punta Penas co on the Gulf of California ; several specimens collected in February 1934, Isla San Estaban in t he Gulf of California; one specimen coll e ct ed on May 1 , 1944 by B . F . Osorio. Sonora P unta Zascosa; one specimen collect e d by H. N. Love in February , 1934 , Tylos niveue Budde - Lund , 1885 F igur ea 5 - 9 Tylos niveus , Budde-Lund , 188 5, p . 278, (orig. deacr ), These isopods are larger than the average of species studied from Mexico, t hough smaller t han T . latreillei discussed i n this paper . They are without pigment. The e y es of thi s species are moderate i n s ize and composed of about fo rty minute oc elli. The first antennae are i mm ovably joined to the head and con sist of a single segment. The second antennae are small and ha\l'e a flagellum of two segments . 40 The external branch of the first maxillae have about ten teeth. One tooth arising from the c e nter of the cluster of t eeth is heavily spined . Two other teeth toward the medial margin have a row of amaller teeth arranged in a comb. The maxi lliped is elongate and narro w. The coxopodite sulcus along the lateral margin of the first thoracic segment extends t he entire length . to seventh thoracic segments are free . The epimera of t he second Those of segments two , three , and four are small , while the laet thr ee are progressively larger . The rear corners of the sixth epi mera are rounded , but the angle between the lateral and posterior borders is less than ninety deg r ees . This differs from T . latre i llei which has the posterior corners more broadly rounded, and the angle formed hy the lateral and rear borderq is greater than n inety degrees . different . T . niveus is quite bristly ; its sixth epimera are The telson is quadrangular and fills the entire border between the extensions of the fifth pleon segment. Localities: Quintana R oo, Cayo Centro; about twenty specimens were collected by B. F . Os orio in leaf mold on November 13, 1947. Q . R oo; one specimen collected by G. Tancah, J . Goodnight on August 12 , 1949. 41 LIGII DAE (Syn, Ligydidae ) T hese are animals of wet a re as . L i g i a occu rs p rimar ily along rocky shores at t he tide line . The multiarticulate antennae, t he e xpand ed triturating surface of the m olar area , the g r eatly el ongated uropods , the eyes with large numbers of ocelli, and other cha racter s class these animals as m or e pri m itive among th e Oni scoidea. The dcrs um is generally quite smooth. The first antennae are mere prominent than in ot her Oni& c oid e a and are three - segmented , fla gellum of the second antennae has ma:4y segments . l acks seta e er penicile . The The molar area T he r e are thr ee plumos e setae on Maxilla I. The maxilliped ha s a five - segment ed palp from t he two segmente d base , Only the species briefly dis'cuss e d b e low are included i n the meage r colle ction~ a vailable fo.- this study . Other spe cies will likely be found , and they are e x pe ct e d to occur along all r ocky shores and in harbors . Ligia Fabril:ius , 1798 (Syn. Ligyda Rafi nesque , 1814) Not many specimens of t his genus c ame t o m y att ention from Mexico. Tno r ough collecting snould r eve al large numbers in seve ra l 42 species . Jackson (192.2 ) revised this genus and for detailed study one is referred to his paper. There are a number of useful taxonomic characters for dis tinguishing the species . variously produced . l ength. The postero - lateral corners of the telson are The branches of the uropods ar e subequal in The male genitalia are distinct in t he species . The maxilliped s and mandibles likewise have excellent species variation. The se , with other characters , should prove very productive for species d ifferentiation when examined under higher powers . Genotype : Lig~ oceanica (Linnaeus ), l 76 7 . Key to the Mexic an Species of L igia 1. Antennae II long , reaching to beyond t he end of the abdomen • • • • • • • • • • • • • • • • • • • • •.exotic3 la . Antennae II shorter , not reaching beyond the end of the abdomen •• • • • • • • • • • 2. Merus and carpus I not flattened 2a. Mer as and carpus I flattened and bordered with a single row of spiny hairs in the male • • • • • • • • • 2 . occidentalis Ligia e xotica R oux , 1828 Figures 10 - 13 . This is a species larger t han L i g ia baudiniana . more than twice as long as wide . Body is little The uropods ar e long and slender . 43 The first ant ennae are minute , but relatively la rger than in L . baudiniana. The demarcation of the epimeron is indistinct , The palp of the maxilli - ped is pr ovid ed with numerous spines on its outer (v entral ) face . endite is likewis e heavily spined a long its distal border . The The c entral p lum o se spine of the first maxilla e is attenuate with five bristl es pro jecting at right angles . Localities : Isla P ichilinque , La Paz , Baja California; several specimens collected Apr il ZZ , 1945 , by C orrea . Vera Cruz , Vera Cruz; several specimens c ollected August 14 , 1947 , by Cardenas and Correa. L i g ia occidentalis Dana , 18 53 Figure 14. This is a large species about twenty - five mm . long and eleven mm . in width. ocelli. The e y es are l arge and quadrangula r and cons i st of many T he second antennae are moder ate ly long a nd slender and have flagellae with about twenty - two segments . bilobed with no plumose bris t les . The second maxilla e are The palp of the maxilliped has five clearly de fined segments . The members of this spe cies differ from those of L . baudiniana in t hat the merus and carpus of leg I are not flattened and are muc h larger in size . From e xotica it d iffers in having antennae II shorter , not reaching b eyond the end of the abd omen . 44 L ocality: Guayamas , Sonora. Five specimens were collected under rocks by Cardenas on October 20 , 194 5. L ig ia baudiniana Milne - E dwards, 1840 Figures 1 5 - 20 This species is less t han twenty mm . in l ength , the body is ovate and over twice as long as wide . shallow grooves . The head is nearly t wice as broad as long , with its front margin rounded . minute ocelli. The ep im era are set off by T he eyes are made up of a large number of The first pair of antenna e are minute , consisting of t hree segments , of which the t erminal is scarcely discernible . The second antennae are long and have a flag e llum of about thirty - four segments . There are five s egments in the palp of t he maxilliped. right a nd left m andible s diffe r somewhat. The The right ba s a row of un - pigmented t eeth below t he heavily cbitinized t erm inal. These are absent in the l e ft . The central plumose bristle of the oute r branch of the first maxillae is short and stout with numerous coa rse setae projecting from it at right angles . This contrasts with t he attenuate slender bristle in L . exotica. Locality: Isla Rasa , Baja Californ ia ; several spe cimens were collected by P rof. Cardenas on De c ember 21, 1944 . 45 STYLONISCIDA E This family was erected as the result of Vandel (l 95Z ) showing that the genus Patagoniscus was a synonym for Styloniscus , a genus previously placed in the family Trichoniscidae . Since the genus Patagoniscus was the type genus for the family Patagoniscidae , this necessitated the change in the family name from P atagoniscidae to Styloniscidae . This family is separated from the Trichoniscidae primarily on the possession of a plumose bristle , simply or variously compounded , associated with the molar area in the mandible . The propodus of leg VII carries a distinctive brush on the disto - dorsal region , The members of the family represented in Mexico are without eyes , are generally cave dwellers , and a1·e mainly devoid of pigment. The genus Protrichoniscus , formerly includ e d in the Tricho niscidae , is placed in this family because of the nature of the mouth parts a nd leg VII armature , A new genus Cuevoniscus is likewise assigned to this family . Key to the Mexican Genera of Styloniscidae 1. Triturating surface of molar area is at right angles to the long axis of the mandible • • • • • • • • • • • Protrichoniscus la , Triturating surface of molar area is parallel to the long axis of the mandible • • • • • • • • • • • • • • • Cue voniscus 46 Pr otrichon iscus Arca ngeli , 1932 The Mexican representativ es of t h is genus are of m oderat e size . Tl,e right mandible has a promine nt plu - No e yes are visible . mose bristle associated with the molar area . The first antennae have , on the t erminal segment , re lativ ely large bristles which may be bulbous or flatt ened structures . The r e is a pronounced brush on the dorsal side of the seventh leg . Genotype : P rotrichoniscu s he roldi Arcangeli, 1932 Key to the Me xican sp.: ciea of Protr i choniscus 1. With four or five segments in t he flage llum of ant e nna e II • • • • • • • • • • • • • • • • la , With t h re e segments in the flagellum of antennae II 2. With curved, flat bristle s on the tip of antennae I . 2a , With large bulbous bristles on ant ennae I c hica n . sp. 2 bridgesi palmitus n . sp. P rotrichoniscu s c hica new species F i gures 21 - 26 The l ength of Protr ic honis cus c h ica i s about 7 mm. and t he width 3 mm . The body is consid e rably flatt ened , prominently flared outward , The epim era are Minute spines ar e scattered over m o st of 47 dorsum . There is no pigment. The second antennae are relatively longer and m ore slender than in th e other s p ecies discussed here ; they are about 4 . 9 mm . long . The flagellum is c omposed of fou r s egment s with a fine penicil on the tip , and it is about a third as long as t he pr e ceding s egment . The head is prominent. There are no e y es . the frontal projects horizontally. of the tho r ax is abou t 3. 4 mm , in most isopods , The region below T he buccal mass is lar ge . The length The l egs are proportionately la rger than Leg VII has a pronounced b r ush. The spine arrange - ment on this l eg is figured , The endopod ites of t he uropods are O. 45 mm . long , and each ends in a stylet , the tip of whic h has a fine b rush of bristles . Antenna I are minute (0 . 45 mm . long ) and appear to be t hree segmented. The tip segment i s provided with a com b of s patul ate bristles . The sexes differ very little . what smaller . T he males obs er v e d were some - Seconda ry sexual char a cters are not pronounced. Adult femal e s have about eleven embryos in the m arsupium . This spe cies differs fr om Protrichoniecus bridgesi in nume rous details . The second antennae ar e m ore s l e nd e r ; the spines of leg VII are diffe r ently arranged . Referenc e to the figures will show more clearly some of the detailed differences . 48 Localities : San L uis P otosi , Cueva Chica , E l Pujal . Male holotype , female allotype , and numeroas paratypes were colle cted by F . Bonet on April 1 and Z, 1 942 . Protrichoniscus bridgesi Van Name , l 94Z Figures Z7 - 38 This is a larger animal than P rotrichoniscus heroldi. length is about 5. 5 mm. and the width is Z. 6 mm . thin , fragil e , and with no pigment. is longest. Its The int egument is The first segment of the mesoeoma The posterior angles of the first three segments are rounded, with the ang le equal to or greater than 90 degree s . and succeeding segments project backwards . Those of the fourth T he dorsum has numerous papillae from which arise minute s e tae . The head is set well into the first segment . minute and three - segmented. flattened bristles . The antennae I are The last segment is provided with curved , Antennae II are slender , and reach the abdomen. The flagellum is three - segmented and a third as long as t he pr e ceding seg ment. This segment in turn is nearly half longer than the preceding. There are no eyes . anteriorly. The buccal mass is prominent and extends ventro- The legs are long and slender , with a scanty, weak spination. The distal ends of the merus and carpus are largely fre e due to the much 49 smaller diameter of the succeeding segment. The seventh leg is provided with a brush of hairs . On the inner (posterior ) faces of the leg segments are patches of grooves , Leg I has a l ong da c tylar flagellum , the tip of which is plumed. The abdomen is distinctly narrower than the thorax. no laterally projecting epimera. There are The ttlson is triangular and its tip is only slightly rounded , and the sides make an angle little less than ninety degrees , Localities : Gruta de loe Sabinas , Valles , Mexi co; on April 3, 1942 , forty - five specimens , including male holotype and female allotype , wer e collected by F , Bonet , Osorio, and Pe lez , Five additional specimens were taken from the same locality on April 21 , 1944, Cueva de Atoyac , Vera Cruz; one immature specimen believed to be of this species was collected by Alvarez and Tellez, on April 30 , 1942 . Protrichon.iscus palmitus new species Figures 39 - 48 These are isopods without eyes or pigment. Length about 5 mm , The flattened head is set very little into the first thoracic segment , buccal mass prominently projects ventrally and anteriorly . The The first antennae are of three segments ; the third segment is provided with about 50 n ine larg e , bulbous bristles . The second antennae are slender and have a three - s egmented flagellum . The first t horacic segment has its posterior corners broadly rounded ; thos e of the fourth form approximately a right angle ; those of the last three are progressively projected backward. The right mandibl e has a prominent plumose bris tle on t he m olar area and one on the lacin ia m obilis . There is a fringe of bristles around t he medial edge of t he molar area. The left mandible has only a fringe of fine bristl es around the m olar area and two large bristles di stally. The l eg s are long and sle nde r . Legs I and V1l are figured . This spe ci es differs from P . bridgesi in having fewer and stouter spines on ant ennae I ; in h a v ing much smaller e pim e ra ; in hav i ng the inner branch of the uropod set nearer the bas e of the basal piece . A comparison of the figures will show t he difference . Loc a lity: Cueva Bustemante , Nuevo Leon. Male holotype and several paratypee w-,re collected by Professor Bolivar on Sept ember 1 5, 1 942.. Cuevon iscus new genus The membe r s of this genu s are minut e , unpi gment ed forms . Antennae II have t hree segments in t he flagellum . Leg VII has a brush 51 on the dorso - distal part of the propodus . The triturating surface is largely parallel to the long axi s of the mandibl e . This differs from Protrichoniscus , which has the triturating surface at right angles to the long axis . Genotype : Cuevoniscus balanus new genus , new species . Key to the Mexican Species of Cuevoniscus , n e w genus 1. L eg VII with t he dorsal - distal portion of the propodus produced forward in a rounded, bristly hump; carpus produced forward and upward in a rounded prominence . yucatanus, n . sp. la. Leg VII with dorsal - distal portion of the propodus not produced forward ; carpus scarcely produced forward , or at most a pointed projection • • • z. Za. F irst antennae with about eight plate .balanue , n . sp. Firs t antennae with about six prominent, clublike . bristles Cuevoniscus yucatanus , Z .irutu~ , r). S~ new species F igures 49 - 55 • Thie is a minute specie s about l . 8 mm . long and 9. 6 mm . wide . The body is without pigment and is flatt ene d . mouthparts proje cting anteriorly. are th ree - segmented. The h ead is flat , with the Ther e are no eyes . The first antennae The second antennae are small with a flagellum 5Z of three s egments . segment. The flagellum i s shorter than the preceding The mandibles have a prominent triturating molar area parallel to the long axis and the right mola r area has a plumose bristle . The first maxi llae are slende r and are mounted with about fiv e t eeth. On t he back , or lateral , face is an extensive area of bristle ~. The posterior c orne rs of t he ante r ior five mesosomal s egments are rounded. Those of t he last two are acutely pointed a nd proje cted backward. The telson is very broadly r ounde d , and is broader than it is long . On its dorsum ar e scattered some coars e , scale - like bristles . The uropods have t h e exopodite considerably longe r than t he endopodite . On the tips of the s e are s e v er al l ong , slende r bristles . T he inner branc h is set far ther posterior ly on a portion of t he basal piece than is the base of th e oute r branch. Leg V1l has the propodus swollen and the d i stal portion e xt end s forwa r d as a thick hump . The carpus likewis e has a large swelling on the d i sto - dorsal side . L o cality : Santa Ma ria , Tecax , Yucatan. Mal e holotype and a p aratyp e were collected by P rofe ssor Osorio on March ZZ , 1937 . 53 Cuevonia cus balamus , new species Figures 56 - 58 • This is a small, blind , yellow - white species . There are a few s c atter ed capitate bristles on the body , more on the head . The three anterior mesosomal segments have their posterior corners broadly rounded. The posterior corners of the fourth are almost r i ght angled ; those of the fifth , sixth , and seventh are progressively produced back wa r ds . The second antennae are slender . The flagellae are indistinctly three - segmented, and about five - sevenths as long as the peduncle , with numerous fine , slender bristles , The terminal bristle is large , its tip mounted by a brush 0£ very fine setae , The legs are relatively long , The sixth and seventh have a pedi- celled brush on the distal , dorsal corner of the propodus above the insertion of the dactylus , This is common to both sexes, Along the dorsal side of th e propodus on all legs is a row of sho1·t, stout bristles numbering about eleven to sixteen. On some of the middle legs this row seems doubled by a parallel row, On leg VII , cleared and mounted in balsam , extending back from the pedicelled brush for two - thirds of the segment, is an unexplained s e ries of thread - like structures . These may be involved in a sensory function in conne ction with the hairs of t he brush , 54 Locality: Cueva Balam - Canche , Chichen - Itza , Yucatan. Male holo - type and two paratypes were collected by P rofessor Osorio on March 29, 1947 . Cuevoniscus grutus , new species Figures 59 - 64 • This is a pale yellow to white species about 6 mm , long and l . 9 mm , wide , The body and head are flattened . head is sinuate with slight lobes at the edges . The front ma r gin of the There are no eyes visible . Antennae II are slender and have what appears to be a three - segmented fla gellum , of which the first segment is t he longest, N e ar t he tip of the preceding segment there is a distinctive tubercle with a spine, along t he base of which are some bristles . The first antennae are provided with about six large , club - shaped setae which are striking in appearance . The mandibles have a large molar process with a large plumose bristle , The lacinia mobilis is likewise provided with a plumose bristle , The sides of the perion are subparallel, The p oster io r corners of the first three segments are rounded; those of the next two form right angles , and those of the last two are projected slightly backward, The first three segments appear to be shortest. The last leg h a s a brush on the disto - dorsal area above the insertion 55 of the dactylis . This has only a very s mall indentation at its point nearest t he dactylis . The rear edge of t he fift h abdominal segment is straight e xcept the extrem e e dg es which a1·e curved down and back. has a broadly rounded rea r ou tline . The telson The margin i s provided with con- spic uous setae . In the mal e th e fi rst and s e cond pleopods are ext ended into long , sl ender s tyle ts . T he abdomen is abruptly narr owe r than the thorax. two segment s have t heir lat eral e dg es fre e . The first The poste rior margins of th e suc c eeding segments are only slightly depressed and extended. This species differs from C . yu catanus in features of l eg VII and in having more teeth in the fir s t maxillae . Locality: Gruta Palmita , B ustam ante , Nuevo Le on. Male holotype , and imperfect specimen mounted on a slide , and several females in a vial , wer e collected by Bolivar and F . Bonet on September 1 5, 1942. T R ICHONISCIDA E The Mexican Tric h onis cidae are readily divided into two sub famili e s , Tr ich oniscinae and the Hapl opht halminae , in ac cor danc e with 56 Verhoeff (I 908 ) and Racovitza (1908 ). Representing the T r ic honiscina e is the genus Trichoniscus , while the Haplophthalminae are represented by Haplophthalmus . In t he fam ily Trichoniscida e t her e are numerous spe cies throughout t he world . Vandel (1 946 ) points out that "a classification of the gr oup which would accord with the phylog eny rests strong ly on an examination of the first two pairs of male pleopods . Here t he va lue in t he light of evolution and classification is unequal b e caus e of com plex variati ons wh ich it is diffi cult to arrange in any logical seri e s . The parallelisms of e volution a nd converg ence make t he use of thes e structu r e s of doubtful valu e . " The Mexican for m s are small, rather narrow- bodied s pe ci e s . The head is not deeply set into t he first thoracic segment. The eyes may b e present , but are few L-1 number , and t hes e ofte n lack pigment , as does the body in most forms. The s e cond ant e nna e are small , and the fla gellu:n consists of th ree or four , often indistinctly separated , seg ments . The tip of t he fla ge llum b ea r s a delicate terminal penicil of hairs . The tclson is broadly truncate . The mandible s carry a definite mola r proc e s s which has no p lumose , brush - like setae or penicils . fe e bly jointed. The palp of the maxilliped is It i s doubtful if t ra chea occur in the externa l pleopods . In the ma les t he inner bran ches of pleopods one and two ar e m od ified for copulation. At t he apex of t he single median penis are found separate 57 openings of the vasa deferentia . The uropods are not opercular. Key to the Mexican Genera of the Trichoniscidae 1, Without prom inent longitudina l tubercled ridges on the d orsum • • • • • • • • • • • • • • • • • • Trichoniscus l a. With pr ominent l ongitudinal tubercled ridges on the dorsum • . • • • • • • • • • . • . • • • Haplophthalmus Tric honiscus Brandt, 1833 In this genus are found sma ll , unpigment ed species , usually with few eyes . E y es w ithout pigment may escape notice , and such forms will be cons idered blind . Verhoeff (1 908 ) makes this genus the type of the sub - family Trichoniscinae . The head is obtusely rounded in fr ont wit h small though di stinct lateral lobe s . The flage llum of the second antennae is usually composed of three or four segments , though the divisions between them are oft en ob s c ure . The first antennae consists of three segments of which the distal is longer than t he second. no p lumose bristl e . The molar area of the mandible has The opercular plates have no air cavities . The basal part of the uropods are rather broad and flattened ; both branches are c on ic a lly t apered and end in a bunch of delic ate hair - like bristles . Genotype : Trichoniscus pusillus Brandt , 1833 . 58 Key t o t he Mexican Species of Trichoniscu s 1. Eyes of one ocellus ; four segments in flagellum of antennae II • • • • , • • , • • , , • • • l a. E yes of m ore than one ocellus , flagellum of antennae II • , • 2. E y es of three ocelli in a triangle 2a, E yes of four ocelli in a quadrangle cruzius n . sp , Three segments in 2 orchidicolis n . sp. , • h octunis n . sp. Trichoniscus cruzius new species Figures 65 - 73 , Thh species is 2, 9 mm , long and had a width of 0 , 93 mm , The dorsum is marbled with light brown on a straw - colore d background, The underside is s t raw - col or e d , The entire dorsum is cov er ed with acute bristles . Thes e are arranged on the thoracic segm e nts rnainly in three transverse rows . One row is found along th e post er i or border of th e segment , the next across the middle , and the third along the anterior portion b ehind that part of the segment which slides under the posterior portion of the preceding . The sing l e eye s are densely black , each provided with a large lens . The head is set very little into the thorax . The posterior corne rs of t he first two thoracic segments are 59 rounded, and thos e of the t hird to the seventh ext end backward pro gressively more . T he l egs of the males and the females are not radically different , The seventh l eg has a fring e of hairs on t he dorsal side of the propodus. On the dorsal face of t he dactylus near its base is a long , flexible , tufted bristle , The abdominal segments have their lateral projections abs e nt; the dorsal plates curve ventrally under the animal , The margins of the third segment continue b eneath and meet at a midpoint by means of a long extension, T he posterior borders of the t e lson are bluntly rounded; the latera l margins are sinuate , Both inner and outer bord er s of t he uropods are conical , T h i s species i s near Trichoniscus halopllilus Blake , but differs from it in having the male external pleopods more tapered; in the details of the male me rus and carpus ; by havbg t he telson rounded rather than truncate , and in being smaller , It differs from orchidicolis and hoctunis by having one inst ead of t hree or £our ocelli, Locality: Vera Cruz , Vera Cruz, Mal e holotype , female allotype and numerous paratypes were collected by F . Bonet on May 31 , 1941 . 60 Trichoni scus orchidicolis new species F i gur es 74 - 79 • This small species is 2 . 8 mm . long and l . 2 mm . wide at t he fourth t hora cic s egment . T he body is slate colored with numerous tubercle s , g iving it a rug os e app e arance . E:ach tubercle i s m ount ed with a short, stout bristl e . The h e ad is set deeply into t he first thoracic segment for ove r two - t hirds of it s length, and it is scarcely O. 5 mm . wid e . s mall , with thre e indistinct oc e lli . T he eye is Th e first ante1ma e are minute . The second antennae have a fla gellum of three indistinct segment s , the t e r m inal of whi ch is prov ide d with a prominent bru sh. The first thoracic segment is longe st, being a half longer than the second . Its posterior corne rs are broadly round ed . t hree segments ar e progressively less roll!lde d . hav e their posterior corners proje cting backward. The succeeding The rema ining t h r ee On e specimen, the femal e h olotype , has five embryos in t he marsupium . The s eventh l eg of t he femal e is stout and prom inently spine d. The abdomen is notic e ably narrower than the t horax. telson is rounded , and its posterior border is almost straight. sp e cies differs from T . cruzius in having more oce lli. The This From T . hoctunis it differs in having thr ee e y es arranged in a triang l e in plac e of four arranged in a rectang l e . 61 Locality: Female h olotype and a para.type were taken at Laredo , Texas , at quaranti ne on March 7 , 1939, from a shipment of orchids out of Mexic o . Trichoniscus hoctunis new species F igures 80 - 8 1 This is a small, fragile species with no pigment. is about 2 mm . and the width about O. 65 mm . The eye spot i s round , black, and about O. 04 mm . in diameter , with four ocelli. barely set into the first thoracic segment. flagellae of thre e segments . whose tip is finely divided. The length The head is The second antennae have The last terminates with a long bristle The first segment is shortest, and the next two ar e progressively l onger . The segment preceding t he flagellum is of about the length of the flag e llum . The posterior corners of th e thoracic segments ar e rounded , except the last , which projects slightly backward . Viewed from above , the posterior borde r of t he first seg - ment forms almost a straight line . in the two sexes . The seventh leg is not very different Leg I in the male is consid erably m odifi ed. The pro - podus has numerous closely - set bristles on its inner face . The telson is broadly rounded and wide r than long . The exo - podite of the uropods is spindle - shaped and tipped with a setae which is 6Z nearly as long as its base. This species has four ocelli , in contrast to one ocellus found in T . cruzius . From T . orchidicolis it differs in having its four ocelli arranged in a quadrangle in place of three dis posed in a triangl e . Localit y : Cueva de Ho ctun, Hoctun, Yucatan. Male holotype , female allotype , and a number of paratypes were taken by Os orio from bat guano on Mar c h 16 , 1947 . Haplophthalmus S c htibe l , 1860 The genus Haplophthalmus is the only genus in the subfamily Haplophthalminae in Mexico. With more coll ecting , the species H. danicus will likely be found more widely distributed in the We stern Hemisphe r e . It is believed to be indigenous to E urope and its occurrence in Utah, Idaho, and in several eas t ern states of the United States indicat es that it is a homophilic species . Its m inute size contributes l arge ly to its escape from detection by casual collectors , This genus has simple e yes consisting each of one ocellus . The longitudinal , raised ridges will readily s e p a rate it from the spe cies of the subfamily Trichoniscinae . Genotype : ltea mengii Zaddach, 1844. 63 Haplophthalmus dani cus Budde - Lund , 1879 Figures 82 - 86 Haplophthalmus puteus Hay , 1899; R ichardson, 1905 In the c olle c t i on there were two spe cimens of femal e Haplophthalmu s danicus from Mexico , D . F . Compar ison with spe ci - mens c ollected at Sa lt Lak e City , Utah , Wallace , Idaho , and in F rance s h owed t he Mexican repres entatives to b e sligh tly l a rger , though in structural details they were identical . The eye is simple and consists of a single oce llus . The meso - soma has a ser i es of longitudinally arranged rows of s mall tubercles on t he dorsum . Viewed from above , the head s h ows t wo d i stinct round ed l a t e ral l obes while the median lobe consists of a distinct tr i angular protuberanc e ; T he minute first antennae have three s egments , all of which are about the same lengt h . much narrower than the othe r two . The t erminal is subcylindric and is On its tip there are fou r bristles . T he s e con d antenna is s mall a nd has a thr ee - s egmented flagellum whi c h has a brush of bristles mounted on its t ip . The flagellum is s hor t e r than t he preceding segment. The first four me sosomatic segments ha ve t heir posterior cor ners rounded , and the remainder have angl e s directed s lightly backward . The telson is subt riangul ar , with its posterior truncate . T he abdomen 64 lacks the rows of tubercles as found on the thorax. The uropods have a stout basal segment with conical rami which are tipped with a numb er of fine bristles . The m outhpa rts are c haracter istic of the Trichoniscidae . The triturating surface of the m andibles face distally rather than medially , as in the other Trich on i scidae . t eet h in t he outer branch. The first maxillae have about eight Three of thes e are on the outside and are relatively larger t han in other Trichoniscoids ; t here is one small median tooth and fou r greatly r e duced t eeth p l aced along the medial bord e r . L oca lity: Mexico City, D. F .; nume rous s pecimens colle cted by F . Bonet in 1943 . ST ENONISCIDA E One of the mo at poorly known families of t he Oniscoi dae is the Stenoniscidae . P rior to t he finding of a specimen in Quintana Roo, the members of t h is fa m ily were known on ly in the Mediterranean region. T he s e for ms are typically halophiles , liv ing in clos e proximity to t he high tide area . Vandel indicates that they are found associated with membe r s of t he genus Armadilloniscus . Very few workers of isopods have had opportunity to e xamine epecimene of t his intzresting fa mily. Aubert and Dollfus (1890 , pp. 68 - 69) 65 create d t he genus St e noniscu s with the sp e cies ple onalis. They pro - visionally placed t he genus in the family Po r cellionidae on the basis of its possessing two segments in t h e flagellum of t he second antennae , S ilvestri (1897 ) described t he species carinatus in the genus Stenoniscus , Budde - Lund (1904) cr eated t he sub - family Stenoniscinae in t he family Oniscidae . Ho weve r , Verhoeff (1917 ), who obtain ed a good series from which he was a ble to make a deta iled anatomical study , raised the St e noniscinae to t he rank of a fam ily . Thi s family a nd t he only genus, Stenoniscus , have no eyes . are n ot capable of rolling into a ba ll. ments i n t he flagellum , The y The s e cond antennae ha ve two seg - The first thoracic s egment has very little of the front corners projecting forward , so the head is essentially free and not s et into the thorax . The molar areas of the mandibl es are r e pres e nted by a low prominence on which there are plumose bristles . Stenonis cus Aubert and Dollfus, 1890 The c haracters mentioned above fo r t he fam ily will suffice for t he genus . S. quintana n . sp. is t he only representative of t he fam ily known from Mexico. Genotype : St enoniscus ple onalis Aube rt and Dollfus , 1890. 66 Stenoni scus quintana new species. Figures 8 7 - 92 This is a small white species . The ey e s are a bs ent. Two specimens are avaiiable and the measurements are given here for both , those of the longer specimen in each case being first . 1. 9 and 1. 7 mm . The widths ar<' 0. 5 and 0 . 47 mm. 0 . 42 and 0 . 38 mm . in length. l . 6 and 1. 4 mm . The lengths are The heads m easure The head and thorax together measur e Withou t the terminal bristle, the second antennae measur e 0 . 37 and 0 . 35 mm . The head widths a re about 0 . 12 and 0. 11 mm . The ventro - lateral edge s of the t h oracic as w e ll as the abdominal segments are g reatly t h ickened , g iving the appearanc e from a ventral vi e w of a series of plates . It would appear from this t hat the animal coul d not roll into a ball. The first abd ominal segment is not visible from above . other £our are prom inently arched po s t e riorly. Th e On either side of t he midline of the dorsum of each abdom inal segment is a prominence making two rows . The l egs are short and c an b e hidden from a dorsa l view. The telson is quite large , and it s upper surface is clearly arched outward . The ur opods are completely c ov e r ed by it. Wh il e t his feature has its counterpart in the Cuban species , Bisilvestria mar rassinii , described by Arcangeli , it differs in other respects . 67 This species differs from the Eur opean species , S. carinatus and s. pleonalis in having less pronounced dorsal ridges , in the details of the uropods , and in other respects. Locality: Isla Contoy, Quintana R oo; holotype believed to be a female and one paratype collected by F . Bonet . SCYPH.A CID.A F.: , Chilton, 1901 The representativ es of this family are small isopods confined to the litto ral regions . They are related to the Oniscidae , and while Van Name retained them in the family Scyphacidae , he questioned t he merits of doi;.1g so . He g ives the following diagnosis which fite our Mexican representatives : "Front not marginec! , but continuous with the epistome . Se cond pair of antennae with flagellum cor.-iposed of four (or five?) articles . First maxillae with the inner lobe furnished with two plumose setae; outer lobe furnished with teeth . Se cond maxilla e furnished with hairs . Mandibles with the molar process reduced , consisting of a low base and a tuft of setae, Maxilliped with masticatory lobe a cutely produced ; palp elongate , much loa ger than m,, sticatory lobe, with articles lar ge and not distinctly defined . "Abdomen is not a bruptly narrower than thorax . Uropoda 68 extending beyond the tip of t he abdomen; inner branch inserted at t he upper , inner angle of the basal article . " Dana (185 2) cr eat e d the s u b - family Scyphacinae in the family Oniscida e . Sinc e that time Chilton (I 901 ), Richardson (1905 ) , Blake (1930) , Van Name (1936) , and Vande l (1943 ) have g iven this g roup full family s tatus , In 1943 Vandel (pp . 12 3 - 24 ) discuss e d nu mer ou s char ac - ters which mer ited the rete ntion of this g roup on the fam ily level . How- e ver , in 1952 , ,n h is E tude des isopodes t errestre s recoltes au Venezuel a par le Dr . G . Ma r cuzzi, Vande l reduces this family to the status of a sub - family . In t h<! key included , the Scyphacinae ar e set off on the presence of four segments in the fla ge llum of the second ant:z,nna . species i s d iscuss ed , Alloni s cu s compar Budde - Lund . One Various cha racters are mentioned , t hough the antennae are m issing from the spe cimen avail able , To my kn.owl edge members of t he genus A lloniscu s have t hree seg - ments i n the flagellum , a characteristic of the Onis cidae . Therefore , t he Mexican A llon iecus are retained in the family Oniscidae , ancJ the genus Armad illon iscus is her e treate d as a represen tative of t he Scypha cida e , Armadilloniscus Uljanin, 1875 This is the only genus represented i n t he material available from Mexico. The front outline of the head i s very deeply three - lobed, 69 The second antennae have four and pos s ibly five segments . The first maxillae have two plumose setae a long t he inner lobe , wh ile the second maxillae are furni shed with hai rs . The mandib l e has the molar process redu c ed , and possesses a low base w ith a tuft of setae . lobe of the maxilliped is acutely produced, The ma sticatory The palp is e longat e and longer than the masticatory lobe , and its articl es are not distinctly defined. The abdomen is not abruptly narr ower than the t h o rax . tion of the ur opods e xtend beyond the tip of t he abdomen. branch is ins ert e d along t he mes a - posterior corn e r . The basa l por T he o u t e r Ve r h o eff states that t here are no tracheae in any of the e xte rna l plates of the pleopods . He als o considers this genus as a subfamily (Armadillonis cinae } of t he On.s cida e , t hough its affinities to t he other members in the Scypha cida e se em to warrant its placement in t hat family . Genotype : Actoniscu s ellipticus Harge r , Armadillonis cus holme si Ar cange li, 1933 F igures 93 - 105 The e llip tical body is covered with evenly rounded tubercles . The head i s deep ly set into t h e first segment . the lat era l lobes are rounded . The m edian lobe i s acute ; The r e are five oc e lli in t he ey es . The first antennae are m inut e ; the second p air have four segments in t he 70 flagellum . in _I!; . The tubercles on the head are small, much smaller than coronocapitalis Menzies , 19 50 . The figures given will aid in placing the species quite readily . The telson is rounded at the tip, and the sides are straight. Locality: Isla Cedros , Baja California ; several specimens collected by Os orio on De cember 16, 1945. Same locality; ten specimens collected by W. L . Schmidt under drifted kelp on July 17, 1938 . A specimen labeled Armad illoniscus perconvexus from Magdellina Bay , L ower California, colle ct ed by W. L. Schmidt , from the National Museum , is considered as A . holmesi . RHYSCOTIDAE The first species of Rhys cotidae described from a North Amer ican specimen was Rhys cotus texensis R ic hardson. The genus was first described by Budde-Lund in 188 5 as a new genus in the Onis cidae . 1904 he cr eated the subfam ily Rhyscotinae . this subfamily to the rank of a family . In In 1947 Ar cange li rais ed This family i s character ized by a great bulbous development of the frontal plate bordered by the supra antennal line. antenna . There are two segn1ents in t he flagellum of the second The maxillipeds are short , with the base very stout. endite and palp are likewise short. The There are no trachea in the pleopods , 71 and g lands occur i n t he epime ra. Only one genus , Rhyscotus , i s known to occur in Mex ico. Rhyscotus Budde - Lund , 1885 The spe cies o f t he genus Rhy s cotus are unique among land isopods in being he r maph rodytic . T he young individuals all appea r to be males , which l ater develop functional ovarie s together with marsupial plates . Howev er , t he male type of pleopoda are retained. Van Name (1924 , p . 200) n otic ed th is c ombin a t ion of characters , but d id not inte r pret it s si gnificance . Jackson (1928 , pp. 527 - 537 ) d iscovered that this anomaly was a t rue cas e of hermaphr odism. Jackson re lates t hat a s omewhat sim ila r condition m i ght ex ist in Philoscia elongata . This genus is distingu i shed by a bulbous expansion of th e epi stome wh ich i s well set off from t he rest of the head by a deep sut ure , and by very short maxilliped s . These have the palp and mala r piece wi de and pr oportionat ely s h or t . T h e right mandible has an e longate corrugate d ridge between t he ma l ar ar ea and the dista l bristles . The abdomen is abruptly narrower than t he tho rax. This genu s previously has been represented in t he Weste rn Hemi sphere by R . texensis in Texa s , and by about ten species in t he West Indies and South America . R . texensis sh.ould occur i n northern Mexico , though no specimens from this area were availabl e for thi s study. 72 Genotype : Rhyscotus turgifrons Budde - Lund , 1885 . Key to the Mexican Species of Rhyscotus 1. Ocelli about ten . . la . Ocelli abo•.1t fifteen colimaris n . sp. laxus Rhyscotus colimaris new species . Figures l 0 6 - l 09 This is a rather small species . the width is about 2 . 2 mm . The length is about 5 mm.; The head length to the head width is about 11 to 14 ; the body length to the body width is about 11 to 5. The abdomen including the telson is about one - fourth of the total length . The general color of the dorsum is a pale yellow with a marbling of brown, confined largely to the latero - posterior corners of the thoracic segments along the lateral and posterior portions of the abdomen. inverted, Y - shaped a rea on the head . with black. There is a brown , The cross furrows are marked The ventral side and the legs are a pale y e llow, almost white. The head is set rather deeply into the tho r ax. are prominent, each consisting of about ten ocelli. The black eyes The first pair of antennae are minute ; the second pair are moderately developed . The 73 flagellum is about as long as th e peduncle; its basal segment is a third of the l ength of the terminal . All of the thoracic segments have thei r latero - posterior corners projecting backward; t he first very little , t he others progres sively more , so that the laot projects to the middle of t he abdomen. The first five thoracic segments are sub - equal in length; the last two are slightly s horter. The latero - poste rior corners of the third to fifth abdominal segments project pro gressively backward . The lateral borders of the telson are distinctly concave ; the posterior angle is broadly rounded . The uropods are prominent. endopodite is laterally flattened and slightly curved laterally. The The exopodite is essentially conical. This species can be distinguished from Rhyscotus laxus by its greater width , b e ing proportionate ly nearly twice as wide . From R . texensis it is readily distinguished by the coloring . Locality: Cuyutlan, Colima; holotype and several, paratypes were collected by F . Bvnet on January 11 , 1943 . Rhyscotus laxus Van Name, 1924 :nguree 110 - 115 The body of this species is long and narrow and r a ther loosely articulated . The l ength to th e width is about 6 to 1. The sides are 74 sub - parallel. The dorsum has numerous fine scale - like bristles , visible only with higher magnification, the appendages . Likewise , numerous fine setae occur on The epistome is pronounced and poss esses numerous setae and fine, darkly pigmented transverse lines . The eyes are large and consist of about fifteen ocelli. The antero- lateral corners of the head project prominently forward and downward. the lateral corners . The frontal line is arched forward except for The second antennae are slender-. The flagellum consists of two setments , of which the basal is slightly shorter . segment preceding the flagellum is equal to it in length . The The toothed chitinous ridge between the left molar tubercle and the c utt ing ridges ir; curved and relatively about as long in this species as in R . t,exensis Richardson, The right mandible has no such ddge in either species . The molar tubercle has three long slender plumose bristles in contrast to the shoi·ter, st,i,ute r two in R . texensis . The ext ernal segment of maxillae I has seven t eeth , three of which are roughened medially. The inner segment bears at its tip two plumose bristles whose basal portion is naked . The first thoracic s egment has its anterior corners projected forward so that the head appears inserted into the thorax. The posterior border of t his segment is arched back conspicuously and the corners are 75 broadly rounded . The poster ior borders of t he se cond and third seg - ments are l e ss rounded, the lat eral borde r forming , with the posterior border , an angle g r eater than a right angle . The fifth , sixth and seve nth segments ar e progress i ve ly more acutely projected back ·ward. Segments thr ee , four and five of th e abdomen are heavily marked with a brown pigment whi ch is in sharp contrast to t he pal e yellow to wh ite telson. T he bran c hes of t he uropods are s h o r t and thick and cover e d with minute seta e . T he male pleopods a re readily inte r - preted from t he figur e s . This species was o r i g inally described from spe cimen s colle c t e d in t he Galapa g o s Islands . Localities : Cuyutlan, Colima; Jan. 9, 1943; s e veral specimens were coll ected by F . Bonet. Acapulco , Gro.; one specimen was taken by F . Bonet on January 24 , 1941. SQUA MIF ERIDA Z In 1893 Budde - Lund d e scribe d several sp e cie s of isopoda which he placed in t he genus A lloniscus , one of the com plex of gene ra treated in t he fa m ily Oniscidae . in which to plac e these forms . ln 1908 he cr ea t ed t he genus Trichorhina Tha t sam e y ear , Verhoeff propos e d the 76 name Bathytropina , whic h is a synonym o{ Trichorhina . In 1946 this genus wa s placed in the s u bfam ily Squam ife rina e in the family P orce l lioni dae by Vand el. F urther study of t he he t er og enous complex in that family convinced hi m t hat t he Squ amiferinae s h ould b e raised to the rank of a family , the Squam ife rida e . This fa m ily also con tains t he genus Platyarthus , not r e pr esented in Me x:ico . The African genu s Ho r a at pr e s ent treated in the family Oniscida e may possibly belong in the Squam ife ridae . The members of this family are of m inute size , gen e rally betwe en 2 mm . and 6 mm . i.n lengt h . T he most noticeable characte r is t h e large numb e r of bulbous or fan - s haped bristles variously arranged , b ut a lway s including a row a l ong the poster ior border of the segments on the dorsal side . The ey es may be present or abs ent , and w hen they occur , the y are small and t he ocelli ar e not numerous . The second antennae are shor t and have two segmented flag e lta e of which the first is usually very s h ort. Trichorhina Budde - Lund , 1 908 Reg arding t h is ge nus , Van Name states that "the m inute size of th e animals , t he prevailing absenc e of striking charac t e rs , and t he small diffe r e nces of for m and d e tail separating the spe cies , th e ir soft integument , which qu i ckly shrinks and distorts its parts when alcoholic 77 specimens are taken o ut for examination, and the ir extr eme delicacy , which b ears little handling with out injury , all combine to make t he ir study difficult . T he i r description , or even their illustr ation in a manner to make their future recognition c erta in without d ir e ct com p arison with materia l , is a difficult matter . " Generally the body has littl e pigment and is usually cove red with numerou s bulbous setae . t he t horax. The head is wide and not deeply set into The s e cond antennae have a two - segmented fla gellum . There appear to be no trache ae in t he e xte rnal pleopods . In 1 933 Verhoeff established the genus Mexicostylu s w ith the species squ a m atus as t he type . Sinc e this genus cannot be separated from the complex of species of Trichorhina i n t his study , it is synonymized here as Trichorhina squamata (Verhoeff) . The relation of Trich orh ina , as designated in this study , to t he Afr ican genus Hora , is not clear . Ba r nard (1932 ) separated t he spe cies in t hese two genera on t he bas i s of t he siz e of t h e two brushes on t he inne r branch of the first maKilla e . Hora has the brushes stout and short. Some of t he Mexican Trichorhina appear to belong to Hora on the basis of t hat c har a cter , but this seems too vague a c haracter on which to s epar ate t he species . The whole compl ex of Trichorhina and Hor a needs investi - gation t o better understand the r e l ations between t hem . 78 The re are six species includ ed in this study. are new. F iv e of t he s e A number of immat ur e s and several i mperfe c t adults ha v e b een set asid e for futu -e study , when additional m a t e rial will be available . Ge n otype : Bathytropa the rmoph ila , Dollfu s , 1908 . Key to t he Mexi can Species of Trich orhina 1. E y es absent 2 la. E y e s present 4 2. Telson is b r oadly round ed 2a . Telson is more acutely pointed . 3. R ight m andible has a large , bifur cate , plum o se bristle • • • • • • • • • • • • • • • • • 3a . R ight m andible without such bifurcate bristle , but with several smalle r plum ose bris tles . 4. Only a singl e oce llus on ea c h sid e . 4a . Ey es w ith more numerous o c elli 5. O ce lli three ; no b ody pig ment. squamatus (Verhoe ff) 5a. Oc e lli s even; d o rsum m ottled. • • • • • • piebalda n . sp. 1coltuma n . s p . 3 atoyaca n . sp. zimapana n . sp. g o:rg osa n . sp. 5 79 Trichorhina xolt uma , new species igures 11 6 - 126 This species is short (length about lj mm., widt h 2 . 6 mm .), broad , unpi gmented and without any visible e y es . The head l obes are moder ate . The fi rst antenna e ar~ minute with very small proxirr,al segments . The second antennae are stout and sm ooth , and th e tips sub - conical. bristl e s . On t he terminal piece t here i s a r ow of about seven s tout The right mandibl e has , in the molar area , a large quad - rangul ar projecti on on wh ic h there is a complex arrang ement of plum os e bristles . The first maxillae have seven t eeth of which t he med ian two are bifurcate . The m axillipeds a re sim ilar to t h os e of T . zimapana. The posterior corne rs of t he first thoracic segment are rounded , less than a right angle , and are curved slightly backwards . Those of the remai n ing segments project backwards in incr easing amount toward the rear . S cattered over the dorsum ar·e numerous small, fan - shaped bristles . Those along t he posterior borde r are l arger and form a conspi cu ous edging . The tclsot1 is broadly rou nded ; its sides are concave . shaped bristles al ong the rear m ar gin are distinctive . of t he telson has spa rs ely s c attered s ma ller br istles . The fan - The remaind e r 80 Locality: Xoltum , Yucatan; ma le holotype , female allotype and numerous paratypes collected by B. F . Osorio and Tafall on Mar ch 24 , 1947 . Trichorhina atoyaca , new species Figures 127 - 130 . This species measures about 4 . 4 mm . long and 1. 9 mm . wide . No eyes or pigment are visible in alcoholic specimens . a pale straw yellow to whit e . acic segment . The color is The head is deeply set into the first thor .- The first antennae are minute , three - segmented and have a row of coarse bristles along the distal inner border , Antennae II are short with a two - segmented flagellum of which the basal piece is less than a third as long as the terminal, which is tipped with a spine , The right mand ibl e has a large bifurcate plumose bristle on the molar area, while the left has two separate bristles , Details of thes e and son,e of the other mouth p a rts can be seen in the figures . The first three thoracic segments have their posterior corners rounded, the third least, The fourth is almost re ctangular while the succeeding segments have their posterior corners projecting backwards . Along the rear margins of thes e segments are rows of fan - shaped bris tles . kind . The remainder of t he dorsum has numerous bristles of th e same 81 The teleon is roughly triangular with the sides concave . The uropods have on th e inner branch numerous l ong , slender bristles , irregularly scattered . From T • . zimapaiythis species differs in having a much s tout er inner branch of the uropod; in having a plumose brush on the molar area in place of a plumose knob; and in othe r details . Locality: Cueva de Atoyac , Atoyac , Vera Cruz; numerous sp e cimens including the male holotype and female allotype were collected by F . Bonet on May 30 , 1 941 . Trichorhina z i mapana , new species F igures 13 1 - 145 Thia is a w hite , e yeless form , whi ch measures about 3. 8 mm . long and 1 . 8 mm . wide . The head is set into t he first thoracic s egment . The l ate ral lobes are distinct. second antennae are short. The fi r st antennae are minute . The The flagellum has the basal piece about a third as long as the distal, and combined , they are shorter t han t he prece ding segment . The right mandible has a molar tube rcle which is plumose and with five plumose bristles distally . The first segment of the thorax has th e posterior corner rounded , the second subrectangula 1· , and the third and subsequent corners projecting 82 backward . The dorsum has numerous , broad , fan - shaped bristles with those along th e rear borders arranged in distinct rows. legs are not unusuaily modified in either se><. The The corn ers of th e last three abdominal segments project backwards . The last projects beyond its rear border by more than twice the visible lengt h at the miciline . The telson is acutely pointed; the sides are concave . The inner branch of the uropod is slender and with a row of bristles , mainly along its medial border . This species differs from ><oltuma in having an acute , pointed telson; from squamatus , g orgosa , and piebalda , it differs in lacking eyes . Locality: Six miles north of Z imapan, Hidalgo , (km . 341 ) at 3100 feet . Collected on January 8 , 1948 , by S. Mulaik. Trichorhina gorgosa , ne w species Figures 146 - 150. In alcohol this specie s is a pale , straw yellow. servat ion , it appeared to be blind. On casua l ob - Howeve r , clos er ei<amination under higher magnification revealed a srn oot h , clear spot a t the place where the ey e might occur. When the specimen was cleared in glyc erin , dark pigment below the surface reveal ed th e presence of one ocellus on each 83 side , The head is not deeply set into the first thoracic segment. The posterior border of the first segment, when viewed from above, for ms a straight line. The posterior corners are only slightly rounded and form n~ore or less a right angle , The posterior corners of th e second segment are similar to those of the first . In the succeeding segments the posterior corn c, rs project backwards . The lateral marginal bristles of the first thoracic segment have been greatly reduced in size , and increased to at least twenty in number , The border presents a closely placed series of bristles . The posterior borders of the thoracic segments are much as in other species in the genus , Locality: Gorgosa cave at Oxkutzcab , Yucatan. colle ctor. E . P . Creaser, July 17 , 1936, Trichorhina squamatus (Verhoeff), 1933 Figures 151 - 157 • Mexicostylus squamatus Verhoeff, 1933 , p . 104 (orig . descr .) Van Name (1936 ) commented that the genus Mexicos tylu s ! established by Verhoeff to contain this species , was very close to Trichorhina, a group whose diagnostic characters and limits have not as yet been exactly determined, 84 Verhoeff in his description stated that the pleopods were without trachea ; the dorsum had numerous leaf - like scales which are figured as having midribs with lateral veins . The species squamatus has three ocelli which readily separates it from the other Trichorhina treated in this study. a frontal line . The head is without lateral or median lobes, or The second antennae are moderately long , of wh ich the terminal haif is light color ed , and their surface has bristles and minute tubercles . The basal segment of t he flagellum is about a third as long as the terminal . The color is brown above with a sprinkling of light spots , par ticularly on the bead . The l ength of the male is 3. 5 mm., and that of the female is 4 mm . Locality: "Chilopa" (probably Chilapa ), Guerrero, in the humus of a mountain fo res t . Trichorhina piebalda new species F igures 158 - 172 This is a medium - sized Trichorhina about Z mm. in length , of which the thorax is l . Z mm.; width is about O. 8 mm . at t he fift h thoracic segment . The head width is O. 4 mm.; t he width of the first thoracic segment is O. 75 mm . The eyes are prominent , consisting of 85 seven ocelli pl aced in the rear , rounded angles of the head. anterior , lateral angles of the head are also rounded . antennae are fa i rly short. The The second The peduncle is longer than the flagellum . The basal segment of the flagellum is about a third as long as the terminal (0 . 08 mm . by 0 . 17 mm.). The figures for the mandibles best explain the arrangement of the penicils . The intei·nal maxillae I are provided with two tet·mina l , bushy peni cils , which are also figured . The most prom i nent chara c ter of this animal is the bi - colored d o rsum of the head formed by having the pigment confined to the anterior third and involving the eyes . colored . The remainder of the head is pale straw In about a fourth of the spe cimens there ie no p igment in the dorsum of the fourth segment •of the thorax. pigment in the seventh segment either . In the majority there is no Over most of the dorsum there are scattered large , fan - shaped b ri stles . The s e are in irregular rows along t he posterior and l ateral borders of the segments . There are about fourteen along the latera l edges of the first thoracic segment. The second male pleopod has two spines on its lateral margin a short distance from t he tip. E xcepting for the pleopods , the males did not differ in any great degree from the females . brood pouch. Females carry from seven to ten young in the On the ventral a i de of the basal piece of the uropods there 86 is a groove, the upper , antP.rior border of which has a fringe of fine bristles . The endopodite is inserted well into the inte r i or of the basal piece and ext ends to t he middle of the exopodite . The telson is s hort , triangular , and t he poster ior corners are rounded ; the sides are almost straight. The length is about a third of the width. This species diffe rs from T . gorgosa , which has ov er twenty smaller spines along the l a teral margin of the first t h oracic segment and from all of the other s in this paper by coloration. make additional featu res clear . with seven ocelli. The figures will This is t he only species encount e r ed A detailed study of all members of t h is genus may nec e ssitat e red e fining th e species belonging to it , T . piebalda may belong to a separate subgenus or perhaps even requi re pla cement in a new genus . L ocality: Villa He rmos a , Tabasco; many s p e cimens , including the ma l e holotyp e , collecte d by F . Bonet on August 14 , 1945 , ONISCIDA E Van Name (1936) retai ned in the fam ily Oniscida" a var i e ty of genera which have be en separated in t his paper i n to the Squamiferidae , On i scidae and P orcellionidae complex. .rtegarding his decision to retain 87 the Oniscidae in the broad sense , he made th e following comment : "My decision is due still more to t he fact t hat in the cas e of many of our t, merican forms we have so little information regarding the details of their structure that often we could not place them in the classifica tion if we had it . " This family comprises genera with the flagellae of the second antennae composed of thre e segments in the spe cies known from Me xico. The pleopods are without trachea . There has be en confusion in t he past whether the Porcellionidae belonged in t h is family , but thi s group has, in t he Mexican representatives only , two segments in the antenna! flage llum , and , perhaps more significantly, they possess trache a in t he pleopods . None of this family are capabl e of rolling into a ball. How- ever , Vandel (1952) returns A r madilloniscus in t h is fa m ily rather t han retaining it in the Scypha cidac . This he does without g iving any r eason. In th e present study of Mexican Isopods Armadilloniscus i s retained in the family S cyphacidae . The various genera represented in the p resent study are r e adily separated in the following key. Key to the Mexican G ene ra of t he Oniscidae 1. Fr ont of head with prom ine nt lat er al lobes . • • 2 la . F ront of head without la teral lobes , or at m o st , indistinct ones • • • • • • • • • 3 88 2. Med ian portion of head projects forward as a prominent lobe • • • • • • • • • • • . • • 2a. Median portion of head between the lateral lobes is broadly rounded forward . • • • • • • • • 3. Carpus of l eg I modified with a row of spines preceding a brush . • • • • • • • • • Hoct unus n . gen. 3a . Carpus of leg I not mod ified aG above • Philoscia • Alloniscus Oniscus Alloniscus Dana , 1856 The body of Alloniscus is convex. The front of the head is produced into a blunt median lobe and pointed lat eral lobes . anten..,ae have a t hree - segmented flagellum . The second The postericr corners of a ll but the first thor acic segments project backwards . maxilliped is densely covered with shor t , fine bristles . The endite of the Among these bristles near the median border is a short , thick, plumose bristle. Budde - Lund (1908 ) discussed this genus and stated that "the molar process (endite ) is without spin es and io covered with short hair s , and the palp is very short and stout". Both mandible s have a free penicil between the s econdary cutting edge and the molar tuft . All of the spines of the outer lobe of the maxilla e I are simpl e , not forked , or toothed. All branches of the pl eopods have trachea in the females but not in the males . The t elson is subtriangular . 89 Genotype : Alloniacus perconvexus .Dana , 1856 . Alloniscus perconvexus Dana , 1856 Figures 173 - 180. The body of t h is spe ci es is ovat e , convex , and almost twice as long a s broad . Specimens range under 5 mm . in l eng th. is mottled with brovm to black pigment . The dorsum The l egs are pale yellow. The head is twic e as wide as long , with t he anterio - lateral corners produc ed into acute horn - like processes which are situated immediately in front of t he e y es . The median lobe is broadly rounded. and composed of about twelve ocelli. The eyes are small The first antennae are minute . The second antennae ar e short and have a three - segrnented flagellum of which the articles are subequal . There are numerous small spines c overing the surface of antennae II. The rnaxillip eds ha v e a palp with th,:ee distinct segments . A long the lateral margins of th e first four thoracic segm e nts , the epirnera are set off by distinct longitudina l sutures which , on the first segment, extends only along the posterior half . Segments five , six and seven do not show sucil sutures . These ani mals gene rally occur a long t he tide line where they readily burrow into the moist sand. 90 Localities : Mangr ove Island , Magdellena Bay, Lower California ; four specimens collected by the Albatr o s E xpedition on M arch 20 , 1911 . San Quin tin Bay, Lower (alifornia ; several specimens collected by M r . Menzies . Cedros Island , L ower California; many specimens collected by F . Bonet. Oniscus Linnaeus , 1758 This genus is primarily of O ld ',\ orld origin and contains few species . Only Oniscus asellus has become established in North Ame rica . The body is broad with well expanded epimera. rn.easuring up to sixteen mm . in length. numerous ocelli. These are large isopods The eyes are large , with T h e second antennae have a three - segmented flagellum . Genotype : Oniscus asellus , Linnaeus , 1758 , "Syst . Nat . ", 10th E d . p . 637 . Oniscus asellus L innaeus , 1758 F i g ures 181 - 185 The body is regularly o val , and its greatest width is more than half the body length. The dorsum is smooth and glos sy. Except for t he 91 lateral lobes , the front margin of the head continues the body curva ture . is set. The first thoracic segment has a deep recess into vmich t he head The three - segmented flagellum is shorter than the segment which precedes it . The side plates of the mesosoma are distinct , and all terminate in backward projecting acute angles . The metasoma likewise has its side plates acutely projected backwards . The first two segments are small and compl etely enclosed by the preceding segment. The uropods have the late ral branch lanceolate and exceeding the inner branches in length. The inner branches are linear , narrow and extend to about t he mid dle of the outer branches . This species is undoubtedly a homophile which will likely be found more ext ens ively in Mexi co than present collecting indicated. Localities : Acapulco , Guerrero; female taken by Borys M alkin , August 2 , 1947, Mexico, D . F.; one speciinen collected by B . C . House on March 5 , 1 940 . Manzanillo , Mexico; one specimen collected by B . C . House o n Mar c h 20 , 1940. Severa l specixnens taken from plants at quarantine at Laredo, Texas . H octunus new genus The members of this g e nus resemble those of the genus Benthana which are South Ame rican £orrr.s , but differ in having only four ocelli , as 92 contrasted with fourteen to twenty - four , and in having a greatly modified front l eg . This latter character is similar to that 0£ Ctenoscia of Spain, but Ctenoscia has a single ocellus and a modified antennae II in t he male while i n Hoctunus the antennae are normal . The outer teeth of maxillae I are heavily chitini zed and the inner are provided with a comb -like series of bristles similar to those 0£ Benthana and Ctenoscia. It shows affinities to Anaphilos cia, but differs in t he maxillary te eth. The second antennae have a three - segmented flagellum . Only the last two thoracic segments have t heir posterior corners projecting backward . Genotype : H octunus murcielago n . sp. is designated as the genotype . :i>.octunus murcielago new species Figures 186 - 195 This is a small isopod in the Onis coidea measuring about 2 mm . long . E xcept for the black eye area , there is no pigment in the body. The1·e are fou r ocelli in each eye which are distinguished with difficulty. The head is convex and scarcely set into th e t horax. are two- , or possibly three - segmented. exi sts , is greatly reduced . The first antennae The m iddle segment , if it The ter m inal segment has two stout , blunt , 93 cylindrical bristles on the tip and two shorter ones on the side . This arrangement of bristles is paralleled in Philoscia colima which is discussed elsewhere . The latte r , however , hao fiv e bristles on tJ-,e sid e . Antennae Il have the first five segments of normal length in. the male . (The single female specimen lacks antennae ). The flagellum is three - segmented , rather coarsely spined , and slightly shorter than the pre ceding segment. On the tip is a long bristle . The first four mesosomal segments have the posterior corners broadly rounded ; those of the fifth form approximately right angle s and those of the last two are acute and projected backwards . The first leg of the male is considerably modified . The carpus carries on its ventral aspect two rows of stout spines and on its inner face near the distal end a brus h of bristles . This is quite unlike the carpus of Ctenosi:ia minima of Spain in that there are more large spines , and the brush is different . The propodus has on th" ventral side of the proximal half a row of fine , short bristles followed distally by four stout spines . This is quite similar to C . minima . Leg VII is not specially modified in either sex. Locality: Hoctun, Yucatan; male holotype , female allotype , and male paratype were taken in bat guano in Cueva de Hoctun by Osorio. 94 Philoscia Latreille , 1804 The members of the genus Philoscia are related to Oniscus . The species are generally small , delicate , and rather narrow - bodied. The Mexi can forms are quite smooth and generally without distincti ve markings or unusual body m odifi cations . The head is not deeply set into the fh·st thoracic segment. It is rounded in front w ith t he lateral lobes , if present , weakly developed. The frontal line is indefinite , and the eyes are composed of numerous o c elli. Antennae I are minute , three - segmented and set close to the base of the second antennae , which arc long and slender . The antennal flagellum consists of three segments . Segments ill, IV , and V of tlle abdomen are produced into back wardly projecting points which sometimes are closely appressed . telson is triangular with its apex :rounded. branches elongate and tapering . The The uropods have the outer The hmer pairs are mu ch shorte r and lat erally compressed . Van Name (1936 ), in discussing the species of Philoscia in th e Wes tern Hemisphere , states that "in the broad sense , Philoscia , even after som e of th e more aberrant species have been split off as distin ct genera , is st ill divisible into a large number of well - marked subgenera and sections , sorne of which ha"e been tr ea ted as full gene ra in recent 95 works , i n some cases perhaps with justice , though I believe that to do so in many cases involves losing si3ht of important resemblances and relations h ips in the effort to emphas ize small differences . 11 The species of Philoscia of E urope have been subdivided into numerous subgenera, but the Amer ican species do not fit into that classification very readily . A study of t he membe rs of this genus on a world - wide basis would be needed to properly evaluat e the place of each in a suitable cat egory. Genotype : Oniscus muscorum Scopoli, 1763 , 11 .;;;nto mologica Car n iolica", p . 415 (orig . descr ). Key to Mexican Spe cies of P hiloscia l. Ocelli 2 1; front of head pointed • la. Ocelli less than 20 ; front of head round e d 2. O celli 3 • • • • • 2a. Ocelli more than 3 3. O c elli 10 in number • 3a. O celli other than 10 in number 4 4. Ocelli 13 or 1 5 in number • • 5 4a . Ocelli 12 or fewer in number . 6 s. No suggestion of a long itudinal dorsal stripe • . ~ n. sp. 2 • ~ n. sp. 3 icacosa n. sp. • richa rds oni 96 Sa. Wit h a distinct dorsal stripe • • • • • • • kanaba n . sp . 6. Ocelli 8 or 9; maxillary t eet h 7 i n number . he r m o sa n . sp. 6a. O celli 12 ; maxillary t ee t h 9 in number • cont oya n . sp . Philoscia col ima new species Figures 196 - 207 This is la rge r t han other members of t he genus available for this s tudy . Length is 6 . 3 mm ., width 2 . 6 mm , The dorsum is heavily mottled with dark brown on a light er background and i s n otic eably spined espe cially along t he posterior marg in of t he segments . The le gs and max illipede are speckled with irr egul ar brown c h romatophores . The body is an e longated oval with th e greatest width at t he t h ir d thoracic segment , The abdom en is not abruptly narrowe r than the t horax and its m arg in is continuous with t hat of t he t h orax. The first four t hor - acic s egments are rounded on their posterior corne rs, the fourth l e ast r ounded with the posterior marg in m aking near ly a rig ht ang l e with t he l ateral margi n when v ie wed from above . ments project progressively backward , T he fifth and succeeding s eg The last e xt e nds backward nearly twice t he width of th e segment at the m idline , The head is half th e w id t h of t he first segment and t wic e as w i de as long . T h i s species differs fr o m ot he r species of Philoscia from Ame rica in the pointed head . There are 21 ocelli in the prominent e y e . 97 The second antennae are slender and reach back to the rear of the fourth t ho r a cic segment. The flagellum is compos ed of three fine d ivisions which are subequal. prece ding segment. Its l eng t h i s equal to t hat of the The profrons forms a d istinct projection between t he antennae . The mandibl es have d istincti ve p lumose bristles . Maxilla e I have in t he outer branch t en t eet h none of which are forked or with com b like structures . The maxilliped differs from that of other k nown species of Philos cia , but m ost nearly approximat e s t hat of t he subgeneric group Ischioscia . H owev e r, P . colima differs from the latt e r g roup in lacking t he fl attened leg s egment in the males , i n t he fewer ocelli, and in t he smooth , unforked te eth in the maxillae . The palpal segment of the maxilliped is lobed nea r t he tip. The s e are heavily covered with setae as are two p roximally placed tubercles . The endite likewise has a heavy brush of fine bri stles along its enti re distal m arg in, a condition which readily distingu is hes this spe cies fr om other species of Philoscia . The l egs are coarsely spined but otherwis e not especially mod i fied . The t els on is subtriangul ar . Its l a te1·al marg i ns are slightly con - c ave and the tip is rounded . Locality: Cuy utlan , Colima ; fema l e holotype and seve11 female paratypes taken on January 3 , 1943 , by F . Bonet . 98 Philoscia vera new species Figures 208 • 214 This species is compact bodied , 'hhen viewed from the side the front of each t h oracic segment is overlapped for a considerable distance by the preceding segment, the width is 1, 2 mm , The length is about 2 , 8 mm . and The sides are almost straight and parallel, Fine pointed spines are scattered over the dorsum , particularly at the margins . The head is set deeply into t he first thoracic segment so that le ss than half projects beyond the front corners of t he t horax, are prominent, There i s a row of abose1 The first antennae .ne bristles on the tip. The second antennae are stout with a three - segmented flagellum of which the parts are subequal in length , eye , There are only three ocelli in each The eye mass forms a distinct protuberance set in a black - pigmented area contrasting to the slightly mottl ed brown dorsum , The mandibles have the la rge mola r brush simple , unbranched but with many cilia . The maxillae I have six quite prominent teeth and several indistinct ones . Two medial teeth have notches near the tip. The first t horacic segment is longest. of t he first four are rounded , The posterior corners The succeeding segments have their posterior c orners progressively more pointed and ext ended backward , The first pair of legs of the male are modified , The last pair are not 99 noticeably modified . The abdomen is a little narrower t han the t horax. terior corners of segments ill, IV and V project backward . The pos The telson is triangula r with straight s i des and a slightly rounded tip. In general appearance this form is dis tinctive from the othe r sp e cies of Philoscia in thi s study . T he six large and several small median t eeth of maxillae I , t he t h r ee o c elli in each eye , and ot her characters set it apart fro m t he othe rs . Comparison with the fig u res for the different sp eci e s will make the difference cl earer . Localities : Vera Cruz , Vera Cruz ; male h olotype , fema l e allotype and numerous paratypes colle cted by F , Bonet on M ay 3 , 1941. E l Hul e , Oaxaca ; female collected by F , Bone t on May 13 , 1940. Philoscia icacosa new species F igu r es 215 - 216 . This is a sp e cies of med i um size . The length of t he female h olotype with fo u r embryos in the marsupi um is 3 , 6 mm . h olotype is about 3 mm , The m al e Th e dorsum is reddish with numerous bristle s, The head is s mall ; its width is l ess t han half th e width of the first thoracic segment , The eyes consist of about t en oc e lli. are short , rather stout and bristly. T he second antennae The flagellum consist s of three 100 segments of which t he termina l is l onger t han either of the other two. The first four thoracic segments have their posterior corners rounded . Segments V , VI, and VII have the corners pointed and pro - jecting backward. The abdomen is abruptly narrower than the thorax. 1'he posterior corners extend backward only slightly. This species is closely related to P . kanaba because of the nature of the modification of leg I . It differs , from kanaba , however , in being more spinose , ill having a differ ent armature of the maxillipeds . in t he number of eyes , and in other det a ils . Locality: Icacos , Guerrero; female holotype and male allotype were collected by F . Bonet on January 1, 1954. Philoscia richardsoni Holmes and Gray , 1909 Holmes and Gray, ?hiloscia richardsoni , 1909, p . 378 (Orig. descr .) fig . 6. Stafford , 1 9 12 , p . 127 , Fig , 71. F i gures 217 - 223 This is a colorless species about 5 mm , long . The body i s oblong oval and slightly roug hened with short , minute spinules . The head is nearly twice as wide as long with an arched front rr1argin and with acute lateral angles . The second antennae are a bout half as long as t he body; the flagellum has t hree segments and i s nearly as long as 101 the preceding segment. There is a spine on the tip . There are 15 ocelli in each eye. T he l,;gg are spinose and increase in length toward the rear . The abdomen is 'lbruptly narrower than the thorax with projecting angles on t he third , fourth and fifth segments . The basal joints of t he uropods are about as long as wide : the enter branch is slender and pointed; the inner branch is hardly a third as lone as the outer , !'luhconical, and its tip is armed with sharp spines . Lo calities : Gedros Id . , Ba ja California, Mexico: ten specimens collected by W. L . Schmidt beneath drifted kelp on July I 7, 1 938 . Same locality; ten specirnens collected by Robert Hoard from under dead agave on July 11 , 1937 . Philoscia kanaba new species F i gures 224 - 230 This species has c ertain affinities to members of the genus Ctenoscia , repr e sented by two species in Spain and Portugal. However , the pr esence of t hir t een in place of one ocellus and other cha r act ers makes me hesitate to place it in that genus . A detailed study of the con - fused subgenera in Philoscia m<>y warrant creating a new genus for lOZ ,. . kanaba or, perha ps , of placing it as a subgen us in Ctenoscia . S uch a study i s not i n the scope of the p r esent paper . P . kanaba has a length of 5 . Z mm . and a w i dth of Z mm . dorsum is glo ss y and heavily mottled with brown . The The under sides of the legs are mottled brown on a pale yellow backg round. The r e i s a m edi an dorsal ro w of light s p ots which giv es the effect of a lon gitudinal strip e . The second antennae are slender and reach to about the m i ddle of the fourth thoracic s egment. T h e fla g ellum is a little s ho r ter than the p receding se g ment . The terminal segment i s about as long as the t wo p rec e ding together . The re are thirteen o celli in each eye . T h e abdomen i s a bruptly narro wer th an the thorax . i s about three tim e s as w ide as it is long . i s a pale ye llo ..v; the rami are bro wn . laterally compressed. terior cor n e r s rounded . The ba sa l p i ece o f the uropods O f the se bran ches the inner i s The first fiv e thoracic segments have their pos The last t wo ext e n d back i n a roun ded projection . Legs I h av e the prop o dus modi fied . d istinct brush . The tels on T he " l? utzapparat" i s a T he ventr al side has a number of sp in es a rranged in a mann er similar to C tenoscia m inima . L ocalities: Male holotyp e , fem a le allot ype an d several paratypes were taken in P alenque R uin s , Chiapas on July 13 , 19 4 9 , and paratyp es frt)m F inca Guatemac , C hiapas on A ugus t Z, 1950 by C larence and Ma rie Goodni ght . P aratypes c ollected by F . Bonet at P uento Morelo s Q uintana. 103 Roo on Novem ber , 1947 an d at £ m iliano Zapata , T abasco on "-ug ust 15 . !'aratypes from C ozum el , Q uintana R oo , collected by P rofessors v sorio and Tafall on N ovem ber 2. 4 , 19 47 . P h iloscia he r mosa new s p ecies F i gures 2.31 • 2.38 Thi s is a much darker spec i es than P hiloscia vera n ew ape cies , and much larger . T h e length is about 3 . 6 mm . in t he male holo t ype . F emale allotype is about 3 mm . l ong . T he width of the male is 1. 8 mm . The dorsum is very smooth an d s h ining , but with a few fine br i stles scattered mainly near the mar g ins of t he p lates . lobes on the hea d . The r e are no lateral The front margin vie wed from above i s rounded. The eyes ar e small and consist of a b out eight oce lli which are pearly in color . Seven are arran ged in a circle wi th the e i ghth in the center . Sev e ral specimens from f- alenque Ruins , Chiapas , had nine ocelli . secon d antennae are slender . The T he flag e lluµ, is thr ee - segmented an d slightly shorter than the preceding se gment. The first two divisions are subequal and together t he ir l e n gth is e qual to the more slender terminal division whi ch bears on its tip two long, stout , bristles and a c lump of nine bristle s along its medial aspect . Ext e rnal maxilla e I have seven teeth of which the thre e inner are forked. tub e rcl e . The mandibl es hav e four pl umose br istl es on the molar Just p roximal to the inner cuttin g edge there i s a tubercle with 104 two plumose bristles which , in add ition, is covered with numerous coarse bristles . The abdomen is abrupt ly narrower than the thorax . The telson is triangul ar and more than twice as wide as long . The sides are straight and the posterior co rner is rounded . This species differs from the other Philosciae of Amer ic a by hav ing only e ight or nine oc elli, by t he prop ortions in the second ant enna! segments , and in other ways . Localities : Vill a Hermosa , Tabasco ; male h olotype , fernale allotype , and numerous paratypes collected by F . Bonet on .A ugust 14, 1 945 . Pa l millas , Tabasco; several specimens w ere collected by F . Bonet in c ultivated soil on A ugus t 18, 1945 . P hiloscia contoya n ew species F igu res Z39 - Z48 This i s a small species about Z. 6 mm . long and l . 4 mm . w i de . The body outline is oval , the g r eat est width being near t he s ixth t hora cic segment. The color ation i n a lcohol i s a m ott ling of reddish brown and y e llow . The darker color i s confined to a narrow , irregular , n1edian dorsal strip , to a narrow area a l ong the marg ins of the epimera , and between these , to a narrower band which is broken in spots . The venter is almost white . than the adults. Juveniles show less pigment 105 The head is rounded both at the back and front margins . lateral lobes are scar cely developed . The Antennae II have a three - seg - mented flagellum which is subequa l to the preceding segment. The pro><imal and distal segments of the flagellum are equal while the middle is shorter . The eyes are small and are made up of about twelve ocelli. The posterior corners of the first three thoracic segments are broadly rounded . Those of the fourth and succeeding segments project backward in incr easing degree until the last extends back an amount equal to the width of the segment at the midline. There are nine teeth i n the outer branch of maxillae I. inner marg i n is a row of coars e bristles . three brush - like protruberances . On the The palp of the maxilli ped has The endit e is truncate with a patch of setae along its distal margin and with another row of coarse setae along the med i al marg i n . The legs are heavily spined . The fi gures will aid best in interpreting t he spine arrangement i n legs I and VII. The telson is broadly rounded. The outer branch of the uropods is nearly twice as long as the basal segment . half as long . The i nner branch is scarcely Both branches are tipped wit h long , slender setae . Locality: Isla Contoy , Quintana Roa; male holotype and s e veral paratypes collected by F . Bonet on November 20 , 1 94 7. 106 PORCELLI ONIDAS Van Name treated the gen era here cons id e red in the family Porcellionidae as belonging to the family Oniscida e . However , in this study, thos e genera in which t he members had trachea in the ext e r na l ple opods were cons idered to belong to t he Porc e llionid ae . T he second antenna generally ha s the flagellum comp os ed of two or t hree s egments . The triturating su rfac e of t he m olar area is obsole te and replac ed by var iously mod ifi e d curve d , plumose s et ae . Only Cylisticus can roll up i n to a ball , t h ough without t he fine closur e obta i ned by the Armad ilidiida e or A rmadillidae . The Por c e llionidae can be separated readily into two distinct gr oup s -- those with trac hea in all, fiv e pairs of ext e r nal pleop od s , the quinquetracheates of Va nde l (1945); and those with trach ea i n t he first two pair of pleopods, t he bitracheat es . V ,mdel farther p oin ts out tha t while there are s ome memb e rs without trach ea i n the e xt e rna l pleopods (atracheates ), this c ond ition in t he P orc e llion idae is a secondary cond ition in some and a primitive cond ition in ot hers . The absence of trachea in any spe cies from Me xico considered to be in t h i s fam ily was n ot noted . 107 Key to t he Genera of Por cellionida e 1. With trachea in all five pairs of ext ernal pleopods. • 2 la . With trachea in the first two or possibly three pa irs of external pleopods • • • • • • • , • • • • • • 4 2. Median lobe of head forms a small but distinct a cute projection. Capable of rolling up . • • • , • • • Gylisticus 2a . Med ian lobe of head obtusely round ed . Not c apable of rolling into a ball , • • • • • , • • • • , , . • 3. Wit h two tubercles of the head giv ing the appearance of a bilobed head , Basal piece of the flage llum much shorte r than the distal pie c e • • • • , • • • • • • Nagara 3a, Without prominent head tubercles . The proximal piece of the flagellum scarcely shorter than the distal • , , • , • • , • Trachelipus 4. He ad prominently trilobed • Porcellio 4a. Head not t rilobed , • • • • Metoponorthus 3 Cylisticus S c hnitzler , 18 53 The members of this genus are re lated to P o rce llio and to Trachelipus , and like the latter genus it has trachea in all five pairs of pleopods . margin . These trac hea open by a number of pores along th e medial It differs from Trachelipus in its ability to roll up into a ball. This is not as efficiently done as in the members of the P rmad illidiidae and A rmadillida e since the ur o pods are e longat e d and not capable of 108 making a tight closur e . This se rves as an e xam ple o f conve r genc e . The first antennae are s ma ll , and t hree - segmented . The second antennae are mode r a t e ly long , with a two - s egmented flage llum . Genotype : Oniscus convexus De Gee r , 1778 , 1 Mem . des . Inse ct es , 1 VII , p . 55 3 (Or ig . descr .) Pl. XXXV , fig . 11. Cylisticus convexus (De Geer ), 177 8 F igures 249 - 253 • This species could be cons i de r ed among t he larger of t he Mexic an terrestr i a l isopods , attaining twelve mm . in l ength . The body is oblong oval , m or e than twice as long as it i s broad , w ith t he s i des The color nearly paralle l . The dorsum is h i ghly ar c hed , and smooth. i s a s lat e gray . The head is short and about a third as long as broad . There ar e large truncate lateral lobes and a small med ian lobe whic h is rather acutely p ointed . The first segment of the thorax is t he largest . Its epin1e ra are large , wit h the posterior corners proje c t i ng back in a cute point s . The pos t erior c orners o f the other s egments project back but l ess prominently . The a bdomen is less than ha lf the length of the thorax . sides of t he last t h r ee segments project back i n elongate point s . The The 109 telson is acute p ointed with the s ides deeply concave . The exopods of the uropods are conical - lanceolate and extend considerably back of the telson. Locality: Several specimens were collected at Acapulco, Gro., by F . Bonet on January 22 , 1 941 . Nag ara Budde - Lund , 1908 Budde - Lund establis hed Nagara as a subgenus of P orcellio with Por cellio cristatus Dollfos , 1889, as the type , t hough it is treated as a genu s in his diagnosis . F or this study t here were numerous rep - resentatives available of N. cristata from numerous quarantine spe cimens of plants at the U. S. border. The most distinctive cha racter is the emarginate front of the head . The lateral lobes ar e quadrangular . There are about 20 eyes . Genotype : P orcellio c ristatus Dollfus , 1889. Nagara cristata (Dollfus ), 1889 Figures 254 - 260 As in the description above , t he front of the head is emarginate . The second antennae are small with a two - segmented fla ge llum . The 110 termina l segment bears a slender spine which is brush - tipped , and near the base of whi ch i s a collar of finer bristles . is three - segmented . The first antenna The basal segment is most stout and longest , t he terminal is more s l ende r and tipped w ith about four thick bristles . The m i ddle segment i s a third as long as the basal. The maxilliped has a t the ape x of the basal pie c e a row of bristles across the entire edge on the inside . The palp is not greatly differenti ated , and appears to be two segmented. The basa l segment is stout and the terminal is slender and mounted with a brush. The endite is rectangular and provided with a number of stout bristles . The mandible has a stout five - branched , densely plumose bristle . Midway be t ween this and the distal cutting edg e is a hummock on which are several plurnose bristles . Leg I of the fema l e is distinctive . The inner face of the propodus bears a broad brush of coarser spine s and fine bristles . The uropods have subconical r a mi. than the inner and about twice as long . the thi rd of the outer branch. The outer is much stouter The inner reaches scar c ely to T he basal piec e is subtriangular . This species is widely distributed in t he t r opical regions of the world, with the type locality given by Oollfus (1889) as Surinam . It has been reported in the V, estern Hemisphere from Costa Rica , Venezuela , Canal Zone, an.cl British Guiana . The collections from Mexico were taken 111 largely at Quarantine along the sout hern border of the United States and the areas o{ orig i n are not generally clear . However , the score of l ots taken at quarantine ind i cate that it is wide spr ead in agricultural areas , and the list ing of numero,\J"~'~fd add little to the knowledge of their distribution, even i{ they were known. Locality : Chapultepe c , Cuenavaca , Morellos . collected by Mr . Seelay on June 28 , 1942. Several specimens were Several score of specimens were taken at quarantine from a number of border towns along the Mex:ican border . These show a w i de distribution in agricultural areas and individual listings add little of value . Dr. Clarence Goodnight collected one specimen from Tea pa , Tabasco , on July 15 , 1947 . Trachelipus Budde - Lund , 1 909 ( Tracheoniscus Verhoeff , 1 917 ) This genus is closely related to 1-' orcellio, but the presence of trachea in all five pair of pleopods together with other characters makes its recognition as a separate genus seem justifiable . The tracheae are little branched and open by a row of pores along the margin of the plates . Antennae II have a two - segmented flagellum . The posterior border of the first thoracic segment is sinuous ; the posterior corners project backward . 11 2 Richardson identified specimens from Vera Cruz in Pearse (191 1) as Porcellio rathkei, though she expressed doubts . The speci - mens available for the present study are consid ered in the genus Trachelipus and resemble P . rathkei but differ in several respects . The first segment of the flagellum is relatively shorter . corner of the first male pleopod is more rounded . is much more rounded . The posterior The tip of the telson This species is designated as Trachelipus richardsoni , new species . Genotype : Porcell i o rathkei Brandt, 1833 . Trachelipus richardsoni new species Figures 261 -- 276. P orcellio rathkei Pearse 1911 , p . l 08 The l ength of the males is 3. 6 mm.; the width is l . 9 mm . at the fourth and fifth thoracic segments . The head width is O. 6 mm ., while the greate st width of t he first segment is l . 6 mm . to the front of t he abdomen is 2 . 8 mm . The length While the abdomen narrows abruptly , the body outline is continued by the lateral m a rgins of dorsal plates 3, 4, and 5. The last thoracic segment has its posterior corners projected behind th e rear margin a distance equal to twice t he width of the segment at the midlin e. 113 The head appears trilobed . The frontal projects in a broad angle , and at the front corners there are distinct , broad ly - rounded lobes . The eyes are large with about 15 ocelli. are minute . The first antennae The flagellum of the second ant e nnae consists of two segments of which the proximal is much shorter than the distal (3 - 10). Parts of the male pleopods are figure d . of external pleopods have trachea . It appears that all five pairs Study of the f igures w ill make a number of characters clea re r . Locality: Huatus co , Vera Cruz; male h olotype , female allotyp e and paratype taken among fallen leaves by P rofessor Cardenas on October 2, 1942. The specimens from Cuatotolapam , V. C., Me x . (Pearse 1911 ) are here considered b e ing i n . this species . Porcellio Latreille , 1804 The species in the genus Porcellio are more or less depr essed with the lateral parts of body s egments expanded. lateral and median lobeD prominent . The head has the Th e first antennae are small , the second are prominent with a two - segmente d fl agellum ; the eyes consist usually of numerous ocelli. The a bdo~en is not abruptly narrower t han the thorax . There are branching trachea in the fir st two, and rarely thre e external pleopods . These open by a sing l e orifice. The telson is tri - 114 angular and usually apically produced . The mandible ha s several penicils b etween the secondary cutting plate and the molar penicil which consists of a tuft of prominent plumose setae . Legs l to 3 and often t he seventh show some secondary sexual modification. This is usually e xpressed in larg er and n1ore numerous spines on the inner and ventral surfaces in the male . In addition , the males have a more distinct brush on the carpus which Verhoeff called the "Putzapparat" or antennae - cleaner . This structure being l es s developed in the females led Barnard (I 932 ) to question why males should "requir e to be cleaner than the females or should require a str onger brush of spines to effect the same puxpose . " He indicates on t he othe r hand that the brush of spines is more like ly for the purpose of better holding th e female during copulation and suggests that Verhoeff might bett er have used t l1e term "Haftapparat" . Genotype : Porcellio scaber Latreille , 1804. Key to Mexican P orcellio I. Posterior corners of thoracic segment I rounded . 2 la. P osterior corner s of thoracic se gment I curved back • 3 2. Ocelli 9 ; body and head with numerous spine - tipped tubercles . • • • • • • • • • • • • • • • • • • scabrosa n . sp. 2a . Ocelli 21 ; dorsum smooth marginali n . sp. 115 3. Dorsum roughened with nume r ous tubercles . • • • scaber Latreille 3a. .Jorsum smooth . • . . . . • . . • . . laevis Latreille Porcellio scabrosa new species Figures 277 - 280 T he length is 4 . 2 mm.; width is 2 . 2 mm ., at the third thoracic segment. Head length is 0 , 23 mm . ar.d the length of the abdomen 1, 05 mm . The dorsum is marbled with brown , conveying the appearance of a longitudinal stripe . The non - pigmented areas are primarily over the areas of muscle insertion, The telson and uropods are pale yellow with very faint marbling of brown. No pigment beneath. The dorsum of the head and thorax has numerous spine - tipped tuber cles . On the thorax th ese are more pronounced along the posterior bord e rs of the segments . Somewhat similar tubercles occur on the abdomen , but they are absent on the telson and ur.opods. The head is set into the thorax. margin of the head presents three lobes . Viewed from above , the fro nt The antero - lateral corne rs are greatly enlarged , squar is h , with t he edges slightly turned up , leaving broad, shallow depressions on the dorsal face . The antennae are rela - tively stout and short , reaching only to the rear of the first thoracic segment . The two - segmented flagellum is 0 . 8 as long as the pec'•mcle . 116 Its basal piece is about half as long as t he terminal . The eyes are conspicuous , dark , and composed of about nine ocelli. The posterior corners of the first two thoracic segments are distinctly rounded , not projecting back. The posterior corner of the third segment forms a right angle , and the succeeding segments project progressively backward . The posterior border of the last thoracic segment is slightly sinuate . Leg I of the ma l e is heavily armored on the ventral surface of the merua , c arpus, and propodus . In addition , there is a well defined "brush" area on the med i al £ace of th e c arpus . The general outline of these two le gs are figured . The single ma l e di d not afford opportunity to examine the pleopods . Locality: Male holotype collected along Pan American Highway at 132 kilomete r s north of Mexico , D. F . , in January , 19 50 , by Stanley Mul aik. P orcellio marginali new species Figur es 28 1 - 285 The length is 6 mm .; width 2. 8 mm . set into the first thoracic segment. of about 21 ocelli. The head is moderately The eyes are l arge , con1posed each The frontal iine is broadly curved forward , giving a bulbous effect to t he frons . The antennae extend back to about t he rear 117 of the third thoracic segment. The flagellum is biarticulate ; the basal piece is slight ly shorter than the terminal , which is tipped by a bristle which has its end frayed into a penicil. The flagellum is shorter than the preceding segment (6 - 7 ). This animal is well pigmented. The dorsum has a marbling of brown with non - pigmented r egions over the regions of muscle attach ment. On t he venter , t he pigment is variously arranged . of the exposed portion of the pleopods has pigment . The rear half The l egs and ventral areas of t he epimera also carry patches of pigment . The posterior corners of the first thoracic s egment are broadly rounded and its rear margin is convex. are curved , but to a lesser degree . The next two segments likewise The remaining segments have their rear corners projecting backwards progressively more from front to rear . The dorsum is relatively smooth and without bristles except for very minute o nes visible along the lateral borders . The telson is acutely pointed; its lateral borders are concave . The uropods have the external branch sub - conical ; the inner branch is laterally flattened . It extends to about the m iddl e of the e xternal , and has on the ventral surface a prom inent mass of bristles with three con sid erably longer ones at the t ip . The poster ior dorsal border of the basis of leg VII has an ex t ensive "rastellum" or rake cornposed of about a hundred closely placed 118 short , stout tubercles . Among them is a posteriorly projecting long spine . This species differs from P . scabrosa n . sp . , which it most nearly resembles , in having a more bulbous frontal region, in the more acutely pointed telson, and i n the absence of pigment distribution to give t he appea rance of longitudinal stripes . Locality: Orizaba , Vera Cruz. Seve ral specimens were collected in moss by F . Bonet on January 14 , 1942 . Porcellio scaber Latreille , 1804 Porcellio m ontezumae Saussure , 1 857 , p . 307 Figures 286 - 291 This is the most common tubercled P orcellio in North Ame rica . It was reported from eastern M exico in Vera Cruz at Tezuitlan , Puebla , by Saussure in 1857 unde r th e name of P . montezumae . P . scaber is larg er t han most other species of isopods found in Mexico. The body is oblong oval and about two times as long as w id e . The dorsum i s convex and covered with numerous rounded tubercles , which give it a distinct rough aspect readily visible to the una id ed eye . The head is deeply set into the thorax. 'fhe l atera l lobes are large and rounded ; the median lobe is not prominent. The lat era l plates of the thorax 119 have their posterior corners acute and pointed backward. The abdomen occupies about a fourth of the body l eng th. posterio - lateral corners are strongly curved backwards . The The antennae are stout with two subequal segments in the flage llum , which is about as long as the preceding segment. Four of the inner spines on the outer lobe of t he maxilla are bifid . The posterior margin of the first thoracic segment is sinuous . The first two opercular plates are provided with branching trachea , which open by a single por e . The telson has the lateral 1nargins con - cave and the posterior corner pointed . The uropods have t he outer branch broadly lanceolate and relatively larger in the males than in the females . Localities : Many localities associated usually with agricultural practices . P orc e llio laevis Latre ille , 1804 F ig ur es 292 - 298 Po rcellio la e vis Latreille 1804 , Hi st . Nat . des Crllstaces e t Insects . VII, p . 46 (Orig . Descr . ). Van Name . 1 936. The Amer . Land and F r esh W,, ter Isopod Crustacea . Bull. Amer . Mus . Nat . Hist . Vol. LXXI , p. I - vii , 1 - 535. 323 fig . Pcrce llio aztecus Sallssure, 1857 . Diagnoses de qllelque Crustac e a Nouveaux des Antilles et du Me xiqu e . Rev . Mag . Zool., (2 ) 120 IX , pp. 304 - 308 . P orcellio cubensis Saussure , 1857 , p . 307 . Porce llio cotilae Saussure , 1857 , p . 307 . This is probably the largest member of the ~scidae found in Me xico and is a common species . It attains a length of over 15 mm . The body is lead - gray in color, oval , and broad , being wider than half the l ength. The ventral surface and l eg s are pal e yellow. The dorsum is smooth. The he ad i a small and its width is less than half the width of the first me sosomal segment. long as the body . The antennae ar e slender and about as The flagellum is shorter t han the preceding segment and with the terminal portion shorter than the proximal. The posterior corners of the t h oracic segments are produced slightly backwards . Segme nts t hree to five of the metasoma have their epimeral plates of modera t e s ize and slightly recurved . subtr iangular and slightly concave above . The t elson is The posterior cor ne r is acute . The first two externa l pleopods have tracheae which open by a single pore in each. Localities : This species has been collected from a variety of localities in Me xico. Its his tory of ready d istribution ov e r much of t he world leads one to believ e it will occur in practically all suitable habitats to l Zl which man has applied modern agricultural practices . Detailed localities will not be given , as they serve but little in determining its distribution. Many specimens have been interce pted at quarantine . Meteponorthus Budde - Lund , 1885 Some members of this genus are separated with difficulty from members of the genus P orcellio. usually a less depressed abdomen. They have a narrower and Van Nam e stat e s that "until further study can be made of the many insufficiently known American species of this section of the family , the adoption of any innovation in their classi fication would be prematu re , and probably would result in more incon venie nc e than advantage . " The first two pairs of pleopods are tracheate ; the frontal portion of the head , the epistome , is not bulbous , but is broadly rounded with the lateral plates not prominently enlarged. In the Me xican species of Metoponorthus there is a m ore or less distinct supra - antennary line . Genotype : P o~cellio pruinosus Brandt , 1833 . Key to the Species of Metoponorthus in Me xico 1. Basal segment of flag e llum of antennae I longer than the t e rminal , • • • • • • • • • • • pruiilosus (Brandt ) 122 la . Basal segment of flagellum of antenna I s horte r than the t erm inal • • • • • • • • • • • • • • • • • 2 2. Ocelli 17 . 3 2a . Ocelli 21 • • virgatus Budde - Lund 3. Supra - ant ennary line distinct, V- shaped . 3a . Supra - antennary line indistinct or absent . saussurei Dollfus • ixma n . sp. Met e ponorthus pruinosus (Brandt ), 1833 Figures 299 - 303 P orcellio pruinosus Brandt, 1833 This specie s is very comm on over mos t of Mexico near agri cultural area s . is broad . The body is oblong and mo re t han twice as long as it It is smooth except for a very fine granulation visible under clos e examination. The head is twice as wide as long , quadrangular with small lateral lobes . The frontal margin is almost str a ight . The first antennae are small , with the last segment slightly longer than t he m iddle one , the body. Se cond ant ennae ar e slender and about half as long as The flagellum is two - se gment ed with the proximal about twice as long as the, distal , wh ich is a g ood character aiding in determining the species. The posterior corners of the first thoracic s egments are broadly rounded , the next three are less so, s lightly backward with acute points . The last tb.ree project Th e a bdomen is abruptly narrower 123 than t he thorax and is about a fourt h of the body leng t h . Locality: Thia species is widely d istribut ed over Mexico , whe r e v er man carri es o n a gr icultu ral work . A listing of ov er twenty loc a lities s eem s s u perfluous . Met a ponorthus v i rgatus Budde - Lund , 1885 F ig ur e s 304 - 3 14 The l ength i s 10 mm.; t he widt h is 4 . 6 mm . T he d orsum is a reddish - brown wit h a rna rbling of pal e spots s o arranged as t o suggest a me dian and two l a t e r a l s trip e s . thoracic segment. The head is set deeply i n to t he first The frontal margin is conv e x , and t here are we ll - developed lobes at t he anterior corne r s . surface . Th ese are conca ve on the dorsal The eye s are small , with Zl ocdli. The fi rst ant ennae are small with ten coars e bristles arranged m or e or less in a crowd ed row a long t he 1nedial b orde L· . T he second antennae are slender . The fla - gellum is as long as the prec e ding segment , with t he proximal segment short e r than t he distal ( 5 - 7 ). The posterior corners of th e first three thoracic s egments are rounded . wards . The corners of the succeed ing segments are proje ct ed back The abd omen is not distinctly narrower than the t horax ; it s margins c onti nue t he contour of t he sides . The abdomen is 2. l mm . 124 long . The thorax from the head to the abdomen along the m idline is 7 . 2 mm . The telson has the sides concave ; the tip is pointed. The legs and p ost erior margin of t he pleopods are marbled with brown pigment . It is a question whether this species should be retained in the genus Metaponorthus . While it has some characters similar to that of such forms as P . pruinosus , it has other characters typical of Porcellio. Until a review of the Porcellio - Metaponorthus complex is made in t erms of species on a world - wide basis, it is best to retain the species virgatus in Metaponorthu s . Locality: 1 m i . N . Villagran, Tam . Jan. 7 , 1950 . by Mulaik . One female collected Tepee . Nayarit , Mex.; several specimens were collected August 7 , 1947 , by Malkin and Goodnight . Metaponorthus ixma new species Figures 315 - 319 This is a species of moderate size , measuring about 5 . 5 mm . in length and 1 . 8 mm . in width . body. The r e is very little pigment in the The head is set well into the first thoracic segment. is about two - thirds that of the first thoracic segment. Its width The antennae are 125 moderate . The flagellum is about O. 8 mm . long . less than the preceding segment. This is slightly The terminal segment of the flagellum is slightly longer tha n the basal. The eyes are distinct , with about 17 ocelli. when viewed from above , arches fo rwa rd . upward. The frontal line , .From in front it is arched The supra - antennary line is distinctly V - shaped. is horizontal . The mandibles are characteristic . mandible are figured . The frontal Details of t he left The second maxillae have eight distinct t eeth . The distal segment of the first leg of th e female holotype is figured . This species is near Metaponorthus davisi (Mulaik) 1942 , but it differs from it in being larger , in having a roughene d integument, and in having few-er teeth in the first ,-.-.axillae. Locality: Female holotype and a paratype from lxmiquilpan, Hidalgo , Mexico. Collected by F . Bonet on Se ptember 29 , 1939. Metaponorthus saussurei Dollfus, 1396 Figures 320 - 321 One specimen labeled :t·orcellionides saussurei was found in the collection of the U. S. National Mus eum . It was labeled as a purchase from Verhoeff , who evidently determined it . The orig inal description by Dollfus was rather brief and il1definite , yet it is assumed t hat Verhoeff 1Z6 had access to the original colle ction with which this spe cimen m i g ht h av e b een compar ed . The following de scription is of the sp e cimen on hand . Ma le , Leng t h is 4 . 5 mm.; th e width is l . 8 mm . a lcohol is a pale yellow. The head is recessed very little into the first t horacic segment w h ich i s th e longest . are de veloped very little , The color in The lateral and frontal lobes There are a bout seventeen ocelli in eac h eye . T he first ant ennae are sma ll and consist of thr ee segments and a brus h like spine on the tip . The s e cond antennae are mo d erat e with two s eg - ments in the flagellum , the basal of which i s about half as long as th .e distal , and toget her they are slightly s h o r t er than the l a st s egment of the peduncle. The poster ior margins of the first £i>1e thora cic segments ar e essent i ally straight from a d orsal view exc ept t hat the post e rior corne r s of the first four ar e slightly rounded forward . backward . The fifth project s slightly The sixth and s event h segments are curv ed backward with the posterior corners p r oJe cting very markedly . The marg in of th e a bdomen is continuou s wit h t he general t h o r acic outline . T he third , fou rth and fift h s egment s a r e pr o g r essively narrower and t neir posterior corners a r e proje ct e d ba ckwards . The t els on is triangular , and its tip for m s approximately a r i ght angle . lat era l m argins are slightly concav e . The The wi dth i s about twice t he length . 127 Dol Hus figured a m inut e spot on the first thoracic segment near the anterior corners , and he states that these are "little pearl like granulations" • A t that spot , close examination revealed a small bristle which has been noticed on other species . There is some question regarding placement of this species in the genus Metaponorthus . strated , No supra - antennary line could be demon - The abdomen is not abruptly narrower than the thorax. How- e·,rer, it is retained in that genus until the Por c ellio - Metaponorthus complex is clarified. Locality: The original locality is g ive n as " Cordova , Mexico " . The speci.lnen id entified by Verhodf is g iven as "Me,dco". ARMA DILLIDII DA;_;:; The members of this family are capable of rolling into a ball, a character which has l ed to t heir common name of pill bug . Only one species , Armadillidium vulgar c , has become v e ry widely distribut ed over the world , and this species occurs in Mexico in nun"\erous locations . The first antennae is t hree - seg m<:nted , hav e a two - se gment ed fla ge llum , The second antennae The head is provided with g rooves into which the ante:mae are folded when the animal rolls up . The ant ennae are expos:?d to the outside , as contrasted to t l1.e enclosing of the antennae 128 within the ball in Arrnadillidae . The telson is truncate and its p osterior border forms a part of t he marginal outline of the body . Thia is not unlike Armad illida e . The uropods have a broad , flat , truncat e , plate - like exopod, which have the posterior border entering i nto the gene1·al body outline . In the Armadillidae the basal segment may form the rear border while the ei<opod is a minute structure often plac ed along the inner border as in Armadillo . Armadillidium Brandt , 1830 The second antennae are capabl e of r es ting in deep grooves , the sides of which form ridges over t he antennal sockets . The epistome has a med ian triangular shield . The m andibl e has several penicils . anterior surface of t he propodus . Leg I has a groove on the This is usually heavily lined with fine bristles. Genotype : Armadill o vulgare Latreille , 1804 . "Hist. Crust . " , p . 48 . Armadillidium vulgare L atreille , 1804 Figures 322 - 325 Armadillo vulgaris Latre ille , 1804 , "Hist . Crust. " p . 48 (orig . descr . ) Armadillidium ciner eum A rcangeli , 1932 , p . 126 . 129 ,,rmadillidium vulgare Budde - Lund , 1885 , p . 66 - R ic hard son, 1902 , p . 304. The body surface is smooth but densely covered with minute , scale - like spines . The color is a dark slate gray, and occasionally some specimens are mottled with yellow or brown . segment I is simple . The epimeron of li e telson is much broader than long, and truncate. The outer branch of the uropod is broader than long and fills most of the gap between the tels on and the posterior portion of the last meta somatic segment. The fla ge llum of the antennae is about as long as t he pre c eding segment , and its first division is a little shorter than the second . The eyes ar e black . This species is common in numerous localities of Mexico . Dollfus pointed out in 1897 that this spe cies is distributed over most of the earth due largely to the activities of mankind . As a consequence , its center of origin is not certain , although the other members of the genus are all of eastern Mediterranea n origin. It is possible that A rmadillidium vulgar.~ likewise had its origin in that region. Localities : Th e representatives of this species are widely d i stributed ove r Me xico. S pecimens are available from over a score of localities . They ar e associated with modern a gr icultur a l practices and will likc,ly be found wherever man carries on modern agr icultur e . 130 E UB E LLlDA.e: Van Name (1 936 ), in his account of the family Cubaridae , which he treated as synonymous w ith Armadillidae, considered that the genera Spherarmadi llo and Scleropact es belonged i n that family . R egarding these two genera , he stated that "there is much to be said in favor of placing them in the Oniscidae rather than he r e . " In the present study Scleropactes and Spherarmadillo are considered less specialized than the genera of Armadillidae such as Armadillo , yet they have little to merit placement in the family Oniscidae , as suggested by Van Name . Vandel (1952 ) considered that Scleropa ct es belongs to the family Z ubellida e , concurring with Verhoeff (1938, 1 942 ), but points out that the systematics of the group is complex and varied . To this family I add the genus Spherarmaciillo. These two genera are t he only representatives now known from Mexico . The flagellum of antennae II is composed of three articles , The posterior border of the sub - triangular telson is broadly rounded in the two g e nera under consideration, of rolling into a ball . Members of this fa1nily are capable I 31 Key t o t he genera of Mexican E ubellidae l, E xopodite of t he uropod is small and inserted along the m iddl e of the inner border of t he basal piece near the tip of t he telson, None of the t eeth of t he maxillae are comb - like , • • • • • • • • • • Sp he rarmadillo la , :S xopodite of urop od inse r t ed near t he inner rear corne r of t he basal piece , Several teet h of maxillae I ar e comb- like , • , . • • • • • Scleropactes Spherarma dillo R ichardson, 1907 The members of t his genus ar e capable of rolling into a ball. T he telson do es not reach the poster ior border , such as in t he genus Armadillo , T he fla ge llum of the antenn<!" are three - s egmenkd . The ur o pods have t he e xopod placed along the middle of the inne r mar g in of the basal pie c e . In add ition to differ enc es of t hese two spe cies gi ven in t he des c riptions , t he y diffe r from S. sc hwartzi in lacking pigment , Two spe ci es are c ons ider ed in t h i s pa pe r , and t hese can be separate d by the following key : Genotype : Spherarmad illo schwartzi R ici:tardson, 1 907 , p . 443 , fig . a - g . Frontal marg i n prominently rolled back forming a distinct groove above it , Int e r nal branches of the uropods extend we ll beyond t he margin of t he basal piece • . • S, huatus co n , sp. 132 Frontal marg in not roll ed b a ck and havi ng only an i ndis tinct g roove above it , Internal branch of the uropods extend only to the post er ior marg i n of t he basal piece , . , , , , , , • • • • • • , , .:,. cuevicola n . sp . Spherarmadillo huat us co new species F i gures 326 - 333 Thie is a s l ender spe cies , me asuring 7 mm . long and about 1 . 8 mm . wide . The color in a lc ohol i s i v o ry , t he fir st thoracic segm ent . The frontal m a rgin i s d i s tin ctly rolled back, l eavi ng a d i s tinct gr oove above it . m ar g i n i s 1. 2 mm . 0 . 4 mm . The head is set into The he a d width along thia Viewed from i n front , t his marg in i s ar c hed about Ey e s are absent . The dorsum is s moot h and shining , though under h i gher mag - nifi cation nu merous minute bri stles ar e evi dent . The ant ennae II are short and stout with t hree segments i n t he fla gellum . with a stout , blunt bristle . This is terminated The segment pr e ceding the fla ge llum is the sarr: e leng th as the fla ge llum wit hout t he spine . The telzcn i s short . !ts po s t erior border is broad ly rounded . It extends only about half way from the fifth se gment to the rear margin of the animal . T he uropods hav e the inner branches short and placed a long th e m iddle of t he inner bord e r of the basal piece , 133 Locality: A female holotype was collected at Huatuec o , Ver . on October 11 , 1943 , by Professor Cardenas . Spherarmadillo cuevicola new species F i gures 334 - 341 The length ie about 4 mm .; the width i s about 1 . 7 mm . head i s short and set deeply into the first thoracic segment. is about O. 94 mm . along the frontal marg in . The It s width No eyes were noted . The first antennae is minute, three - segmented , and tipped with a tuft of bri stles . ments . The second antennae are stout with a fla ge llum of three seg The terminal bears a stout bristle . short est; th-a other two are subequal. This basal segment is It differs from S. schwartzi R ichardson in which t he middle segment is shortest; the other two are subequa.l . The sulcus of th e lateral margin of the first tho r acic segment extends as a groove along the posterior half of the margin. of the groove is finely striated longitudinally. The surface These striations continue to the anterior edge of the segment . A band of similar striations con - t inues across the front of the head . The inner border of th e sulcus do~s not project as far back as in S . schwartzi. The dorsal integument is smooth; though under higher magnifi - 134 cation there are visible m inute bristles , which are scattered over most of t he surfa ce . The color i s a pale y ellow with no ind ications of any markings as found in S . schwartzi R ichardson. There is only a slight indication of a frontal r id ge , and it is v isible only under highe r magnification. Thi s d iffe rs from t he very p rominently rolled - up border of S . huatusco n . sp. Leg I is p rominently sp ined . On the inner face of the c a rpus is a distinct brush of coars e bristles , the "putzapparat" of Verhoeff. The area on whic h this brush rests is comparatively flat , contr as ting with the swelling found in S. huatus co. The sulcu s of the first tho , acic segment extends forward along about half tha margin. The sulc us has very fine longitudinal striation s wh ich continue forward be7011d the limits of t he gr oove to t he front edge . Loc ality: Huatusco , Ver . M . Cardenas . One f.,ma le taken on October 11 , 1 943 , by Male holotype taken in Cueva de l os Sabinas Valles S. L . P . by F . Bonet on Apr il 2 , 1942. Scl eropactes Budd e - L und , 1885 This genus is s imilar in many ways to the rno re common Armadillo . It differs in having the telson broadly rounded , sub - t r iangular , 135 u.nd shortened so tha t i t does :iot ~xtend t o tb.e anim 2.l. l"(!<lJ.." bord e r of th~ Tne plurnose bristle of srn:ne of the leg s a L.:io di:~:tingu ishe ,; it f -r om t ha t g ;.~ nu s . Th~ ey~o are S i.TI dl _1 :ud fev:, in nu:rY1 b e:r . of t '~e genus Sci:,ro pactes a r c, c a p:tble of ,·olling into a b a.1 1. lateral lobes of the head are prominent , Me r.c be Ttt T he The front of the head is lobed . Other speci es in this ge nus are found commonly in Central Arr1er ica and wes t ern S c.uth A rnerica . Genotype : S cleropactes concinnus B ud de - Lund , 1885 , p , 240 , S cl eropactes c edrosa n e w species F igures 342 - 346 The specimens available are small . mm . The leng th is about l. 7 The head i s not deeply set into the first thoracic segment . When viewed from above , all but the first t horacic segments show the pos terior corne rs projecting backward . about ().3 mm . long . Th,e abdomen i s sho rt , being The telson does not reach to the rear border , The internal urop ods extend back as far as the posterior corne rs of the basal piece . The outer branch projects slightly farther and is set in the i nternal rear corner of the basal piece . 136 Antennae II are sho t t and stout , and they ar e provided with a flagellum of three s;,gm.:,nts . The outer branch of t he maxillae are distinctive . Nea r the tip , along the outer margin, is a la rge brush of long setae . The fiv e medially - placed teeth are pectinate; the Ollter four are smooth. inner margin . ture . In addition, th.:,re are two plumose bristles near th e T he figur es will make clearer the natur'! of this struc - The end it e of the maxilliped has a bi - lobed tip. Leg Vil has a long , t hree - branched plumose bristle which arises at the base of the dactylis . There i s little difference in the l egs in the two sexes . Locality: Male holotypc and female allotype colle ct ed by F . Osorio on Apr il 4 , 1945 , on t he Isla Cedros , B . C . ARMADILLIDAtc This family is ci-..aracterized by a highly arched body , capable of being rolled up . The epimera are well developed and so formed as to enable t he anilnal to assume a spherical shape . In many Armadillo the margins of the anterior segrncnts have:: grooves and notches , making int er locking , tight - fitting , opposing edges , facilitating the formation o{ a smooth sph<ere . Van Name (1936) points out th::.t this tight fit and the adaptation of the pleopods for breathing dry air permits such effe ctive 137 conservati on of moisture that many species can maintain t hemse lves in semi - arid regions of the tropical and warm temperate zones . The short head is deeply set into the t h ora><. antennae have two articles in the flagellum . The second T he large , broad , basal segments of t h<': uropods aid in enclosing the body when rolled up , while the internal and especially the external branches are greatly reduced . Usually all five pleopods are adapted for air breathing , the external plates being richly supplied with tracheae . Armadillo Latreille , 1804 T:1e genus :~,.!??a~~~ll-9 presents a number of morphological features which set it off readily from other related genera . of t he se cond antennae is two - segmented . The flagellua Its basal segment is appar - ently shorter t han the terminal , at l eas t in t he Me ><ican material available . The las t segment of t he ped,incle of the antenna is usually longer than the flagellum . The animal is capable of rolling up into a ba ll . The approxima - tion of the marg i ns of the post<:rior segments with the anterior is very effective in e nclosing th e delicate underside of t he anima l to m inimiz e evaporation. This enclosure is made more effe ctiv e by the presence in m any sp e cies of a coxopodal sulcus along the lat eral margin of t he first thora cic segment into which the marg in of the abdomen is in serted . This 138 sulcus is formed by the dorsal scute and the epi meron of the coxal piece . Usually th e re is a coxopodal cleft at the post e rior corners of the first segment . In some spec, ,s the inner border of the cleft is greatly reduced so that there is scarcely a job in the outline of t he inner bord e r (A . boliveri). Such a notch is present in the rear corners of the second thoracic segment in a number of species . One species , A . articulata , has notches along the inner margin of all of t he tho ra cic segments . In Armadillo the rear of the telson is truncated , and this edge is a part of the general outline of the animal and adds to the efficiency of rolling up . The basal piece or protopodite of the uropods likewise enters into the uniform outline of the margin . The cndopodite is usually quite small and i s it1s erted on th e inner edge , usually at the base of the protopodite . The exopodite is even smaller and is inserte d along the inne r margin on the dorsal side some distance from the rear of the protopodite. The size range is from thr ee mm . in A . minutus_ to twenty - seven mm . in stuckchensis . The body surface of the different species is quite variable in texture and sculpturing . In A . boneti and A . soyotlanis th ere ar e prominent tubercles , whereas in t he others the integum ent is markedly smoother . Armadillo carries its young in a brood pouch much as in other gener a . The number of young is no doubt variable among the different 139 species , but little information on t h i s subject could be gathered from the material . Th e two sexes can readily be distinguished by the presence in males of distinctly modified ext ernal p lates of the first two pairs of pleopods . The m axillipeds , wh ile differing among t he species , do not lend themse lves to ready use in taxonomy . Mor e study will b e needed. There is characteris tically a small coxal piece , a flat basis to whic h an epipodite i s attache d n e ar it s proximal external border, and on t he ti, of the bas i s medially i s a s ma ll endite and a t hree - segment ed palpus placed latera lly . On t he ventral fac e n e ar the distal end of the basis is a ser i e s of spines which seem fairly constant i n number for a ll of the spe cies . Only their arrangement varies . The memb ers of this genus are weak - lim b ed with poor powers of locom oti on , so t hat t hey do not range very far . V ao< n Name (1 936 , p . 328 ) s tate s that " Spe cimens fr om widely separated places , or from different islands (unl ess th ey are close t oget her ) will u s ually pr ove to be different species . " Thi s seems to be true for the spe cimens avail - abl e for t he present s tudy. Genotype : Armadillo offi cinalis Latre ille , 1804 . 140 Key to the species of .A r ma dillo l. No sulcus visible along the lateral border of the first thoracic segment • • • • • • • • • • • • • la. A sulcus present for at least part of the lateral 2. T he dorsal surface is slightly irregular , tending to fo r m tubercles . Ocelli 17 • jung laoris n . sp. Za. Dorsal surfac e smooth • • 3. Basal piece of flagellum is only 1 /4 as long as the terminal piece ; oc e lli 10; a small species • minutus n . sp. 3a. Basal piece of flagellum longer than above 4. Basal piece of flag ellum about half as long as the terminal ; ocelli 23 . • • • • . • • • • . • • • . bolivari n . sp . 4a . Basal piece of flagellum about one - third of distal 5. Ocelli 15 or mo re acapulc('.colis n . sp. Sa . Ocelli 10 • • • • • • benetisla n . sp. 6. Leg I armed with stout , sharp - pointed and capitate spines ; ocelli 27; basal piece of flagellum of antennae are more than half the length of the distal piece • stuckchensis n . sp. 6a. Leg I not so armed ; ocelli less than ZO . 7 7. Sulcus of the first tho r acic segment extends along th e entir e lateral border . • . • . . • • • • . • • • 8 7a. Sulcus does not extend the full l eng th of the lat eral border of segment I . • • • • • . • • • 8. Body cov ered with large coarse tubercles ; ocelli 4 or 5 • . . • • . • . • • • • • 2 6 border of the first thoracic segment • . 3 4 5 12 ~neti n . sp. 141 9 Sa . Body comparatively smooth; oc elli more t han 6 9. Z y es 13 . 11 9a. :E;y es 16 . Pearse 10. A cl eft; in th e rear corners only of tne first and second thor acic segments. • • • • • • • • pelaezi n . sp. I 0a . .4. cleft in t he r ea r corners of the first three l 1. Sulcu s exte nd s forward s c ar cely one - fourt h of the leng th of th e marg in • • • • • • . • • mexicana verhoeff I la . Sulcus great e r in extent t han a four t h of the m a rgin • • 12. Dorsum w ith lar ge , coarse t uber cl es 12a . Dorsum smooth or at most with fine granulations • • • 14 I 3. Sulcu s extend3 forward about thr ee - fourths of the marg i n • • • • • • • • • • • • schultzei (Verhoeff) 13a . Sulcus e xt e nds forward less than three - fourths of the margi n • • • • • • • • • • • • • • • 14. O c e lli 18 ; eulcus exte nds forward about half of t he m arg in of t he fi rs t thoracic s egment . oaxacana n . sp . 14a . O c elli 16 or less . • . 1 5. Basal segment of antenna! fla g e llum about half as long as the t erm inal • • . • • • . • . • • dugesi Dollfus 15a . Basal segment of a nte nna! flag<!llum abou t a third or less th e lengt h of t h ,:, term i nal . • • • . • . . • • 17 16 . No coxopod al cleft on t he rear corne ,·s of t he first thoracic s eg ment . • . • • • 18 segments ; a jog in the fourth • • • • • • • • . colimaoris n . sp . • • • • • • . 13 s oyotlan i s n . sp . • • 15 • • • 16 142 16a , With a coxopoda l cleft on the rear corners of the first and second t hora cic segments articulata n , sp . l 7. Length about 9 mm .; sulcus visible from a lateral view; the inner border projects behind the outer • • • • • • • ma rtir a n , sp . l 7a , Length less than 7 mm ,; sulcus not visible from a lateral view and its inner bord er does not project beyond the lateral • • • • • • • • , . • • • . , osorio n . ap, Armadillo junglaorius new species F igures 347 - 351 Th is spe cies belongs to the subgenus Venezillo. The cleft at the posterior corners of the first thoracic segment does not proje ct forward to form a sulcus , While it is similar to A . ra msdeni Boone , it differs from it in several characters , Viewed from the side , t he ventro - lateral margin of the first t horacic s egment forms almost a straight line , The inner branch es of t he pleopods are somewhat tri angular in outline , It appears to be more tuberculate , The length is about 6 . 5 mm .; t he width is about 3 mm , The posterior border is broadly round d ; t he anterior is som ewhat truncate , The head is highly arched , Viewed from above t he ma r g in of t he epistorne is not v isibl e ,except at the lateral corners due to t he forward ar c h i ng of the head . The dorsum is roughened by numerous e longate t..ibercles , 143 These are indistinct on the abdomen . On the t"1son there is a trian - gular tubercle on the upper median part. The lateral margins of the thoracic segments are all slightly projected backwards . There is a coxopodal cleft on the first thoracic segment , its inner border projecting below and behind the outer . Tnia cleft scarcely extends foreward . On tl·.e inner border of the cleft of t ne second segment is a finger - like projection visible from the side . The e dges of thoracic segments two to four ar e ac ut e ly row1ded ; the others are truncate . ments are subequal in length along the median line . All of these seg The posterior tuber- culate portion is r aised a little above the anterior portion , which fits b,meath the p r eceding segment. The general ground color is a pale y ellow. The posterior thoracic borders are flecked with brown, which ie in a broa der area on either side of t he m idline , giving the appearance of two longitudinal rows of spots . The antennae are snort; th e flagellum is about equal to the pre ceding segment; its proximal portion is about a third as long aa the distal . The ant ennae are brown except for some white flecks and the white fla gellum . The venter is whit e exceµt for the t>Oaterio r epimera , whic h ar e finely flecked with brown . There are 17 occlli. The telson is more than twice as broad as long ; its posterior border is about half a~ long «s the anterior . The uropods are small , 144 the ir external branche s minute and projecting at nearly rig h t angles to the surface of the basal piece . The inner branches are long er , somewhat triangular , and surmounted by bristle s nearly as large as the whole ext ernal branches . Locality: Colima , Potrero Grande ; female holotyp e taken in jungle growth by F . Bonet , January 15 , 1943 . Armad illo minutus , new species Figure s 352 - 355 This is a small species of about 3 mm . in l e ngth . is highly arched . The head is set into the thorax . The body Viewed from in front , the frontal appears high ly a rched , b e ing O. 64 mm . wide at the edges of the frontal and O. 16 mm . h igher at th e middle than at the edges . The e yes are large , compos e d of about t e n ocelli. Viewed from above , the frontal is only slightly arched forward , and the back of t he head is nearly stra i ght . The antennae are l arge for the animal , thickened , wit h the basal segment of the fla ge llum about a fo u rth the l ength of the ter m inal. The post er io r corners of the tho ra cic and abdominal se gments are prominently projected backwards . The cleft on t he rear corne r of the first thoracic segment is scarcely projected forward into a brief sulcus . 145 The inner projection i s l ess rou nded , so it i s visible from the s i de . In s i ze a nd general feat ures t his species approxi mates A . pa r vu s . How ever , i t diffe r s in hav ing little or no sul c u s, in the flatt e r fr o nta l region , and the absence o f a pr ominent groo ve i nto whi ch t he a n t e n nae fit when t he ani m a l i e r o lled up . L o cality: Miramar , Manzanilla, Colima . Ma l e holoty;,e , female allotype ?nd several paratypes were co ll ected by F . Bone t on January 16 , 1943 . Armadillo bolivar i, new species Figures 356 - 361 Thi s i s a large , flattened form . The antennae are slende r with the basa l por t ion of the flagel.lum aboc,t 'Jne - half the lP.ngth of t he d i stal po..-tion . There is no thor acic sulcus . The co><opod ite ridge of the first segment is reduced to a slight p r om i nenc e or job in the outline i n the rear o f the lateral par t of t he segment. Thi s is well removed from the posterior late ~al angle and the l ateral margin of the segment . This species , represented by one specimen , the fema l e hol o t ype , i s c ream - c ol o r ed in a l cohol with faint blu is h marbiing along the basis of t ,1e epimeron. The legs are white . Length about 10 mm.; the wid t h a c ross the first thoracic segment is 8 . 3 mm., the width acr o ss 146 the head at the eyes i s 3 . 3 mm ., and the leng t h of the head at the midline , v i ewed from above , is about 0 . 5 mm . The upper border of the epistome is distinctly upturned , slightly convex forward, with a med ian broad indentation. Vi ewed from in front this bo rder i s slightly depressed along the middle . head is broadly concave . The posterior border of the The dark e y es have twenty - thr ee ocelli. The epi meron of the thorax are very large and flare outward with the posterior corners projecting posterior l y . T'ne thoracic seg - ments are subequal along the m idline . The telson is longer than w id e (S - 7 ). It is constricted near the m i ddl.:, so that its narrowest width is a little more than one - half that of its base . the base . Thia constriction is about a third of the d i stance from The exposed portio;, of t he basal segment of the ur opods is about twice as long a s broad , and the lateral borders are sub - parallel. T he ext ernal branch is about 0 . 4 mm . l ong, slender , and placed in a notch on the med ian border of the ba.sal segment above t he middl e . The i nternal branches of the uropod s are visible only from below , are small , and are about two - thirda as long as t he e xt ernal branches . The posterior part of the thoradc segm ents is little ra is ed above the anterior p ortion of the succeeding segment, which slips under it . The posterior lateral angles of t he first thoracic segment ext end back and are fairly acute . The lateral marg ins are broadly rounded from 147 a dorsa l view. The antennae are short and slender . The two - segmented fla ge llum is shorter than t he peduncle (3 - 4 ); its proximal segment is half t he length of the distal . There is a faint purple marbling over most of the antenna , especially beyond the basal segments . While this species is similar to A . acapulcacolis , new species , and A . benitisla in lacking a sulcus , it differs radically in general appearance . It is much larger and has the external branches of the uropods of different form . The descriptions and figures will make the differences clearer . This specimen had nume rous eggs in the brood pouch. Locality: Mexico, Vera Cruz , Atoyac ; "Bosque y cafetal ; sobre plantas . C. Bolivar y F . Bonet leg . " (1 specimen female ). Novembe r 12 , 1941 • .Armadillo acapulcocolis new species Figures 362 - 365 Length is about 4 . 3 mm ., width 2 . 3 mm . Head width is 1. 4 mm . The body is moderately arched ; the l ateral margins do not flare outward . Viewed from above , the rear marg in of the head i s concave , the front margin is broadly convex. The epistome forms a distinct up - tur ned margin which is somewhat appressed to the head along the middle . 148 Viewed from in front , this border is rather h i ghly arched, The an - tennae are quite short ; the flagellum is shorter than the peduncle (11 - 15 ) and its proximal segment is about a third as long as the distal. The eyes are large , consist i ng of about 15 cicelli, The coxopodite forms only a slight j o g in the outline of the inner margi n of the first thoracic segment; this is removed some dis tance from the lateral and poster ior borders . There is no sulcus . T h is jog is even less pronounced on the inner border of the second segment , The dorsum is slate - colored e xc ept for small white spots on the dorso - lateral sides and a diffused gray spot along the m idline on tne anterior of the second to s i xth t horaci c segments , marbled with a purple network , bluish gray . The legs are white , The under side of the epimera are The legs are short , The telson is wider than long (1 1 - 9) and a trifle narrower along the rear border than the length, It is constricted abruptly above the middl e where the width is two - thirds that of the anterior border , The uropods are somewhat rectangular with the external branches long and conical, and from a dorsal or ventral view, they distinctly project beyond the rear of the telson. The inner branches are also quite lar g e , The posterior corners of the thoracic segments are project e d backwards moderately , those to the rear progressively less . The lateral 149 borders of the first segments viewe d from above and fro m the side are convex. The lateral border of the second segment i s sharply round e d, the third and fourt h quite acute , the remaind e r truncate . A . acapulcacolis can be distinguished readily fro m the other forms discussed here by the length of the branches of the uropods and the absence of a sulcus . Localities : Guerrero , Tierra Colorado. A ca pulc o , Guerrero. Female h olotype and several paratypes were collected 3 miles west of Acapulco under a rock by S. Mulaik on January 3 , 1949. One female paratype collected by F . Bonet at Tierra Colorado , Guerre ro, on January 2 , 1945. Several specimens were collected by Bonet at Cayaco , Guerrero , on De c ember 28 , 1944. Seve ral spe cimens were collected by M . Gar - denas at A capulco , Guerrero on July 24, 1943. A r mad illo benitisla new species Figures 366 - 372 The general color of the ma le holotype is a pale yellow with s ome brown marking s . The first two t ho r a cic se gments are brown along the middle third with this coloring extending laterally along the p ost e rior margin to t he posterior late ral corners . The rest of the segments are more widely pigmented with only t he ante rior , lateral corne rs clear. 150 In general , t he body is smooth , On higher magnification t he surfac e appears fine ly roughened by backward pointing tube rcles , The epimera of t he thoracic segments ar e nearly vertical , Viewed from abov e , or fro m the s ide , the l a t er al border of t he fi rst segment is gently curved outward and downward , Its posterior corners ar e broadly rounded and have a coxopodite cleft , The e xternal border proj ects behind t he internal , e xt e nds below the external , Viewed from t he side , t he internal bord e r There is practically no sulcus along t he lateral borde r , being only abou t one - s e venth of t he m arg in. This is slight ly rolled outward , for m ing a distinct depression above for most of its l ength. There is a distinct coxopodit e cleft on the second thor a cic segment whose la t e ral m ar gi n i s truncate with the corne rs rounded . The late ral margin of the t h ird and fourth are rounded , t he remainder being truncate . _A ll of the t hora cic segments bu t the last have their pos t e rior corne rs p r oj e cting backward s . The la t e ral portions of the abdominal segments flare o ut ward and project backward . The t el s on is wider than long (33 - 24 ). Its p os - t e rior bor der is little m ore t han half as wide as t he anterior border (18 - 33 ). It i s slightly cons trict ed abollt t w o - t hirds fro m t he base . uropods hav e t he e xt erna l s egment s ma ll . The It proj e cts towa rd t he rear margin because of its m a nn er of insertion. The front marg in of t he head vi ewed fro m above is only slightly 1 51 c urved outward . The m iddle port i on is quite straight. The frontal line is clearly arched upward and backward , with its midd l e p ortion r ather clos e ly a pp ress ed and it s la t era l edges forming a slight s helf. The eyes a re dark and each composed of about t en ocelli. From above , the late ra l b order of t he first t hora cic segment is straight. Loca lity: Mal e allotype and female allotype colle cted on Isla Benito , Costa W. de B . C. by B . Os orio on May 30 , 1944. Arm adillo stuckc hens i s , new spe cie s F i gures 373 - 379 • This is a large form measur ing over 18 mm . i n l ength and about 7 mm . in width. ment . The head i s set b ack int o t he first thoracic seg - There are twenty - seven ocell i i n each ey e a r r anged r oughly into four rows . The frontal line is arched upwa rd and has behind it a pro - nounced gr oove for its full length . The first ant ennae are small . The se cond are moderate , and when turned back ward they extend t o the rear of the first thoracic segment. long as the peduncle . The flagellum i s about five - sev e nths as The basal segment of th e flagellum is about three - fifths as long as the terminal . The antennal depress ion is we ll e xcavated ; t he antenna! fossa ar e s e t on prom i nences . A long the lower lateral sid e 152 of this is a distinct antenna! tubercle , The cleft at the rear ang le of the firs t t h oracic segment eKtends forward about a fourth of the leng th of the segment, The outer bord er is much more rounded and shorter than the inne r , and so s ituated that from a s i de v i ew, the inner border is seen to project behind and below it . There is a distinct cleft on the rear co r ners of the second segment , Leg I i s fairly stout and armed with both sharp - poi nted and knobbed spi nes , Viewed from the media l s ide there are six knobbed spines proje cting vent ra lly on th e carpus , Near the ante r ior ventral s ide , and slightly abo ve the firs t t wo kno bbed spi nes , are t hree stout point ed ones , Set diagonally a c ross the inner face of this carpus is a s hallow g roove border e d with a dense , brush - like arrangement of bristle s , which project distally. This brush is so pl aced in relation to the head parts that it might serve as an antenna e c leaner . Spines are found on the merus . F'our of t he se are knobbed , but progressively so from distal to proximal , while the fifth spine in th e row is pointed , The second and t hird pair of l eg s like w i se ha ve such knobbed spines , but the se are less obvious , None w e re noted on the r emaining l eg s . On t he ventral side of t he pro - podua of t he first l eg ar e two rows of stout spine s similar to thos e on the ou ter face of the carpus , which flank the knobbe d spines , V iewe d fro m t he side , the dorsum of th e abdomen makes about a 45 d eg ree angle with the basal margins of the segments . Th,;, telson i s 153 constricted near the middle . The narrowe st point is about two - fift hs of the distance from the end of th e segment . Its p osterior border is slightly less than the l ength of the s egment when viewed dir e ctly from the posterior and about four - fifths of t he l ength across the front bo ,·der . This lar ge spe ci e s, whil e repres e nted by a single spe cimen , is quite distinct ive . The combination of lar ge size with a large number of ocelli , the proportions of the parts of t he fla g ellum and this to it s peduncle , precludes its ass i gnment to any known for m . A generic revision m i g ht warrant placing this in a s epa rate subge nus , L ocality: Sant iago , B . C. One spe cimen , the ma l e holotype , collect e d by M . Correa under rocks on Mar ch 23 , 194 5. A r m adillo l>oneti new species F igures 380 - 385 This spe ci es , r e presented by a male , is sma lle r than A . s oy atlanis n . s p , The tube rcle s a re less e l e vated and are blunter. The coxopodal cleft has its inner border proj e cting b ehind and below t he outer . Body is hi ghly arched ; when seen from abov e , the small e y es , cons is ting of four or fiv e ocelli, are not visible , being obs c ured by d o rs o - l a t e rally proje cting tubercles locat ed above t hem . The epimera of t he t ho r a x are not visible from above e xc ept t he anterior p ortion of t he first seg ments since t hey proj e ct ventrally , and t hey ar e hidden by the lateral tube rcles , 154 The sulcus extends for the enti re length of t he first th oracic segment and ends in a cl eft behind . It has its inner border projecting poste riorly and somewhat ve nt ra lly to the outer border . a side view. The sulcus is v isibl e from There are di stinct clefts on the pos ter ior angles of the second segment into whic h the ant er ior border of t he t h ird segment fits . The later al tubercles above t he epi mera of the second to sixth thoracic s egments are enlarged and their anterior bases so modified that they for m notches into wh ich t he preceding epimera articulate when the animal is rolled up. The poste rior tube r c ulate portion of the tho ra cic segments is rais ed above the anterior po r t i on which s lips beneath t he rear of t he preceding segments . The tho racic tubercles are arranged in two irr e - gula r transvers e rows on the d oraum , but they become one row on t he sides above the epi me ra. The telson is wi der than long (9 - 5). slightly more t han half as wide . The p osterior border is The r e is scarcely any c onstr iction . The uropods ar e small with t he e xt ernal branch very minute and s et in the inner border. This species differs from A . soyatlanis in that the lat ter mar g ins of the first thor acic segment are not visible from above . 155 L ocalities : Mexico , Guerrero , Colotlipa , Cueva d e Jutxlahuaca; January l 7 , 1941 ; male holotype . Chiapas , Huixtla ; De c e mber 28 , 1939 , F . Bonet , collector . Armadillo walkeri (Pearse) , 1911 Cubaris walkeri P8ARSS , 1911 , p . I 08 (ori g . descr . ), F i g s . la - If. P earse 1 s des c ription and figures are here reproduced : "Cubaris walkeri , new species . -- Body convex , minutely granulate ; tho1·acic s egments ea c h with an e longated swollen mass of bl ended tubercles on each side l mm . from the m iddle line . Head more than twice as wide as long ; anterior margin straight , strongly refle x ed ; eyes rathe r lar ge , sixte e n ocelli. Antennae with flagellum shorter than last joint of peduncle ; first joint of fla ge llum less than a third as long as s e cond . F irst segment of body separated by g rooves from the lateral margins w h ic h are somewhat reflexed; lateral margins of other thoracic segments narrow , strongly flexed poste riorly ; first coxopodite free along whol e outer margin , divergent at poste rior e nd ; second coxo podite fre e along out e r end and anterior margins , divergent at ou t e r edge. P leo - telson strongly constricted in t he m iddle , about as wide as long , width at distal end one - fourth less than at proi<ima l end ; a low tubercl.e nea1' proximal m argin in me dian line . Uropod a with bas a l segment a little longer than wide ; inner branch robust , s patulate , mor e t han half 156 as long as pleo - telson , attached on the posterior inner margin of basal segment ; outer branch small , conical , inserted more on the dorsal than ventral surface of the basal segment at the m iddle of its inne r marg in. Color of alcoholic specimens slaty; a series of longitudinal median white blotch es along the segments from the head to the ple o - telson; lat eral marg ins of first , third , fourth , and all abdominal segments more o r less white . .Locality: Dimensions : 1 1 by 5. 5 millimeters . 11 Cuatotalapam , Vera Gruz, Mexico, under leaves and stones at low elevation. Type in University of M ichigan Museum (Pearse ). A rma:lillo pelaezi new species F igures 386 - 400 Thi s species belongs in the "subgenus Vene zillo" according to Van Name , because th-:, sulcus of th e first thoracic segment extends the full length . It differs from the other closely relat e d forms in having t he basal segment of the flagellum about a fourth as long as the distal . On the dorsal side at the tip of the peduncl e of the antenna! flagellum is a bristl e at least three times as long as the others on the segment. The body is highly arched ; the anterior is truncate with the front margin almost straight; the rear margin is broadly rounded . From 157 above the rear of the head appears slightly concave , the rear margins of t he thoracic segments , except the lateral portions , are practically straight with a tendency toward a slight convexity in the last two, The posterior corners are slightly projected toward the rear , the last two more than the others. The eyes are large , with thirteen ocelli, From a side view the sulcus i s visible for its whole length and ends in a cl eft at the rear , Its inner border is muc h more acute than the outer and extends below the outer , The inner border of the cleft of the second segment is quite acute and does not extend beyond the outer. This cleft is continued forward as a slight sulcus , The anterior corner of this segment at the base of t he epimera is prolonged forward to form a process which fits into a pocket on the rear of the preceding segment , Similar forward projections are found on all of the succeeding segments of the thorax . The general color is a pale yellow with the rear part of the raised port ion of the segments of the thorax being a slate purple , abdomen and telson are much like the thorax in color , The The uropods ar e yellow , The width of the telson is greater than the length (9 - 7 ); its rear border is about equa l to the length. There is a constriction of the lateral borders ; it s narrowest is less than a third of the distance from the pos terior horde r . 158 Near the middle , on the underside of the epimera of the fifth , sixth and seventh t horacic segments , is a fairly well developed border or jog formed by t he coxopodite , On the seventh segment t his border is most pronounced , and in the region just behind the coxa it forms a definite cleft behind a conical , finger - like projection, The abdominal epimera articulate into this cleft , The rnax:illipeds , female ext ernal pleopods I and II, and t he fir st le g are as figured , Localities : Gruta de Cacahuamilpa , Guerrero, A bout ten specimens were collected by F . Bonet, C. Bolivar and D. Pe laez at 1 , 100 meters. Gruta de Acuitlapan, Guerrero . Several specimens were taken by Bonet , Pe laez and Osorio on N ovember 11 , 1943 , Gro. Gruta de Yux:tlahuaca , Severa l spec imens were taken by Bolivar and Bonet on June Z6, 1946 . A rmadillo colimaoris , new sp e cies F igu r es 401 - 403 Thi s is a dark brown species with a s ulc us on the lateral edges of t he first thoracic segment reaching practica lly the whole length . From a lateral view this sulcus is readily visible since the inner border extends a bit ventral to t he out er . The cleft at the rear corner has its inner 159 border rather acute and projecting beyond the broadly rounded outer border . outward . The outer lateral border of this segment is rolled slightly Therefore , above this border is a broad , shallow furrow which extends near ly to the rear of t he segment. There is a less pronounced coxopodite cleft on t he third thor acic segment with the inner border toward the anterior margin. The fourth and fifth segment show only jogs or breaks i n the outline, with no cleft. The dorsum , especia lly anteriorly , is roughened by large tuberculate areas over the dorso - lat eral areas of muscle attachment. These areas have white spots . On the anterior , dorsal portion of the first thoracic segment along the mid lin e is a tumescent area which extends laterally into acute points . The head is rather hi ghly arched so that the dorsal surface makes almost a right angle with the profrons , the latter of which is pra ctically horizontal. The width of the head across the eyes is about two - thirds that across the first thoracic segment. ately large with thirteen ocelli. The eyes are moder - Vi ewed under higher magnifications , the dorsum appears roughened with minute , pointed tubercles . The second to fifth thoracic seg,nents have their lateral m a rgins broadly rounded , the sixth and seventh are truncate , with only the corners slightly rounded . The anter ior portion of the dorsal surface of these segments are abruptly depressed below the posterior . 160 The abdomen is highly arched . Vi e wed from t he posterior the height of the telson i s less t han half the he i ght of the abdomen. This he i ght is about two - thirds t he width ac ros s the lateral edges of the th ird abdominal se gment. The first a nd second s egments are exposed so t hat in the slightly curled animal they are as wide a s the othe r t h ree . Th e t e lson is almost vertical , fo r m i ng a right angle with the ventral or lateral e dg es of the a bdom inal s egments . e dges are scar c ely cons tricted . Its lateral The width of the anterior border is much greater t han th e lengt h of the e xt e r n al portion of t he segment (22 - 15). The width of the post erior bord e r is slightly l ess than the l e ng t h (14 - 1 5). The uropods are m uch light er t han t he telson and a bd o men above , lacking t he dark pigment . Its inner branches are flattened postero - ant er iorly; the external branche s are minut e , being scarcely 0 . 03 mm . in l~ngth . The antennae are rather sho r t , m odera t e ly stout ; the flagellum lacks t he dark pigment of t he peduncle a nd is about e qua l to t hat joint . The proximal s egment of t he flage llum i s about a fifth as long as t he distal without its t erminal bristle . The legs are white exc ept for a brownish marbling on some of t he coxae, and a dark brown terminal claw. Locality: This species is re pres e nted by a s in g l e specimen, a male coll ected by F . Bonet at N e vada de Colima , J alis co , on January 21 , 1943. 161 A rmadillo mexicana (Verh oe ff ) 1933 Microdillo mex:icanus Verhoeff , 1933 , p . 98 , 100 (O rig . des cr.), fig 1 - 4 . Verhoeff cr e ated a new genus , M icrodillo , for t h is species . In th e same paper he described Venezillo sc hultze i and made a detailed listing of c haracters for each to justify his generic pla c ement . H owe v e r , he took n o cognizan c e of t he many other new - world sp e cie s in t h e ~ d illo (Cubaris ) complex. An examination of one of h is specimens of Microd illo mexicanus does not s h ow it to b e worthy of s epa rate gener ic placeme nt. Van Name (1 936 ) stat es t hat "in color , general for m , and app ea rance and c haracte r of the body surface , t hi s spec i es muc h resem bles C. sc hultzei , t h ough of sma ller s iz e . " Armad illo soyatlanis new spe cies F igur e s 404 - 409 The b ody is highly arc hed ; when seen from above , the anterior e nd is truncate , the poster ior rounded , the sides almost st r aight . cpimera flar e outwa r d considerably . The The dorsa l surface i s ornan,ented with l a r ge , rather acute , t i pped tubercles ar ranged in two transverse rows on t he p o s t er i or ha lf of t he second t o seventh thoracic segments . The first t hora cic segment has four tra nsverse r ows . ar e t h r ee such rows . On t he head t he r e Vi ewed from above , the first abdom inal segment 162 is short , smooth. The exposed parts of the segments bearing the tubercles are raised abruptly above the anterior part that slips be neath the segment i n front . The front line of the head is almost straight; the epistome forms an upturned, soniewhat forward-flaring border . Viewed from below , this border forms nearly a straight line for most of its length. The eyes a r e fairly large, convex, with about twelve ocelli. The antennae are rather stout, short; the flagellum is about equal to the last segment of the peduncle. Its proximal article is less than a third as l ong as the terminal one. The lateral margin of the first thoracic segment is flared out• ward, forming a horizontally extending border, on the ventral side of which the coxopodite sulcus is developed less than a third of its length. The sulcus ends behind in a notch whose inner border scarcely projects beyond the outer. On the second thoracic segment, and to a less extent on the others, the large, lateral tubercles are so formed as to produce ledges a l ong their anterior bases. The posterior corners of the pre- ceding segments fit against these to produce a tight articulation when the animal ie rolled up . The coxopodul cleft on the second thoracic segment is less pronounced and is little more than a prominent jog in the outline o f the inner border . 163 The tel son is wider than l ong; the posterior border is about three - fourths as wide as the front b order. Below the middle the telson is constricted to about three - fifths as wide as the front border. In the upper hali are two large, rather p ointed, po steriorly directed tubercles. The uropods are small; the external conical segment is minute, set near the median border. The inner branches are also minute and oval. Viewed from above , the first abdominal segment is hidden be neath the rear of the preceding segment; the second segment is narrow. The third to fifth segments are subequ al in width , and each are provided with fo ur prominent tubercles . T he color of the raised portions of the segment s of the epime ra and the head is a slat~y-blue, except that the tubercles are generally white. The portions of the segments which slip under the p receding segments are crea m to white . Likewise, the uropods are white. B e- neath, the animal is also white except the telson , which is bluish - gray except for the narrow white border The female does not differ greatly from the male . It differs from f:: •_boneh , which is a ve ry coarsely tubercled form, in ha ving a much shorter sulcus, in the greate .r number of eye s , and in the r e lati vely lon ger basal portion of the flagellum . L ocalities: M exico, &an Luis de So yotlan . Male hol otype, fe male 164 Localities: Male holotype , f emale allotype and several paratypes from L a s H um e da des , A rmeria in C olima collected on Januar y 19 , 1943; nume rous paratypes collected at Villa Herm osa ; one s pecimen A ll specimens from San L ui s S oyotlan, Jalisc o on Januar y 6 , 19 43 . taken by F . Bon e t . A rma di llo schultzei (Verhoeff) 1933 Venzi llo schultzei Verhoeff, 1933 , p . 98 , 102 (orig . descr. ) C ubaris schultzei Van Na me , 19 36 , p . 51 8 . Ver hoeff plac ed the species in the genus Venezillo , which he rais ed from the status of a s ubgenus . T h e following desc ription i s quoted from Van Name (1 9 36 ) . " The coxopodite sulcus on the margin of segment I i s stated to extend three - fourths of the length of the mar gin. (T his , however , i s n ot v i sible in Verhoeff' s figure , ) The, gen e ral body surfac e i s dull and enti r ely free from g ranulations , but is clos ely undulated an d verrucos e on t he thoracic tergite s . The rear bor de r s of t he t ergi tes of se gments I to Ill are almost strai ght, " Segment II ha s a long , rather narrow coxopodite process whi ch reaches n earl y t o the rear mar gin of the epim eron. The thoracic epi - mera a r e not bent or flared outwar d , except slightly so in the anteri or 165 part of the body. The anterior border of the head forms a flattened, obtuse angle and is onl y weakly developed, and without any sharp edge . A lateral border on the first thoracic segment is slightly indicated on the anterior part only. " Ocelli in four rows. on the basal joint. Se venth legs of the mal e with a process F lagellum of the antennae with the first article twice as long as wide . " Locality: No specimens which could be identified with this species were available for this study. The type locality is given as " Near Chilopa" (probably Chilapa), Guerrero , M exico; in humus of a mountain forest . Armadillo oaxacana (Van Name) , 1936 F i gures 41 0 - 414 . Cubaris oaxacana Van Name, 19 36 : p . 56 (orig. descr . ) F ig. 215. F our specimens of what are believed to be A rmadillo oaxacana were taken by Boli var, P elaez and O sorio in T axco , Guerrero . Van Name reported it from San Geronimo , Oaxaca. The anterior thoracic segment s have the l ateral ends sharply rounded; the b ody surface is smooth. are eighteen ocelli. The antennae are short. There The cleft at the rear of the first thoracic segment 166 is deep and is continued forward as a sulcus to a point anterior to the middle . F rom a side view this sulcus is partly visible . The anterior border of the telson is about a third wider than the length. The telson is constricted in the middle . There is a cleft along the anterior border of the second thoracic segment forn1ed by the anterior edge of the coxopodite and the epimera . The posterior edge of the coxopodite which forms the cleft on the first segment fits into this cleft on the second. Details of the tip of the maxilliped showing the nature of the endite and the palp are figured . Localities: Taxco, Guerrero . F' our specimens , including the male holotype , were c ollected by Bolivar , P elaez , and Osorio. Van Name described the species from specimens collected at San Geronimo , Oaxaca. Two specin1ens were collected at Tepoztlan, Morelos by M. Correa on June 22 , 1941. One specimen was collected by Bonet at Acapulco , Guerrero on January 24, 194!. Armadillo dugesi Dollfus, 18 96 Armadillo dugesi Dollfus , 1896 , p . 47 . Cubaris dugesi Richardson , 1905 , p. 652 . The body is short, convex, smooth and very finely bristled. The head is deeply set into the first thoracic segment, and its slightly 167 curved front margin ecarcely extends beyond the front of this segment , Eyes are s mall , with about 14 ocelli . The flagellum with the basal segment is slightly turned out for its whole length. The sulcus is present but it extends forward for only about the posterior third. There is a distinct coxopodite cleft on the second segment. The telson is as long as it is wide, and the sides are concave. Locality: Corritos (Silao) and M orelea, Mich. , Mexico . Armadillo articulata new s pe cies ,figur es 415 - 4ZZ . This is a fairly large spe cies , slatey-gray in color above with some paler marking s . convex. The body is comparatively smooth and moder ately The length is about 9 mm . , width about 4 . 5 mm . Viewed from abo ve , the front margin of the head is slightly convex, the rear margin much more so. each. The eyes are n1oderate with about 14 ocelli in The upper margin of the epistome forms a border which is curved upward and is somewhat appressed to the head along its middle half. The antennae are slender; the flagellum is shorter than the pre - ceding segment , its basal piece is about a third as long as the distal. The first thoracic segment is about l. 5 times as wide as the head. Its posterior lateral corners are slightly projected backwards. The lateral borders are rolled outward and lightly upward so as to form 168 a distinct furrow nearly the length of the border. coxopodite cleft at the rear corners . There is a distinct This cleft is projected forward as a sulcus for a distance less than a third of the length of the border . The inner border of the cleft does not project as far back as the outer , but projects ventrally so that the short sulcus is readily visible from a side view . The other thoracic segments project slightly backwards , the edges of the second to fourth are rounded, the remainder are som e what truncate . The posterior half of each of these segments is slightly raised above the level of the anterior half. There is also a distinct deep cleft on the posterior l ateral corner of the s e cond thoracic seg me.n t . The inner border does not reach the exterior . On the other thoracic segments there are also coxopodal enlargements which form distinct jogs against which the anterior edge of the succeeding segment articulat e s when the animal is rolled up . The anterior edge of the third abdominal segment ha s the edge , which articulates with the cleft on the last thoracic segment, distinctly rolled and enlarged. The telson, when viewed at right angles to its surface , is one and a half times as broad as long; the anterior border is a b out one and a fifth as wide as the posterior b order. The uropod s are distinctly longe r than wide; the slender external branch is O. 15 mm . lon g , set well above the middle on the median border . The internal branch is stout, narrowly ov al and about a half mm . in length. i69 The epin1era are a slate color below. ar e flesh colored above and below. The uropods , however, The antennae are colored much as the dorsum, This species apparently belongs in the subgenus Venezillo. It differs from A. oaxacana in having fewer ocelli and in the placement of the external branches of the uropods . The telson is more constricted than in A . dugesi , and the posterior corners of the first thoracic seg ment flare outward. Localities : Mal e holotype , female all otype and numerous paratypes from Cueva de Jutxlahuaca, Colotlipa, Gro . , Mexico; collected by J:'' . Bonet on January 17 , 1941. Numerous specimens were taken by C . Bolivar and B. Osorio from Presa Guadalupe, Mexico, on August 22 , 1943. Armadillo martira new species Figures 423 - 427 This species is larger than most other species of A rmadillo considered in this paper . is a pale straw. It is about 9 mm. long . In alcohol the color The body i s finely tuberculate with rows of tubercles along the rear borders of the segments . In addition, there are large "hump s" formed by confluent tubercles, which are especially noticeable anter iorly . i7 0 There is a distinc t coxopodite cleft on the posterior corners of the first thoracic segment . This is continued forward as a sulcus for about a third of the length of the l ateral border . Viewed from the side , the inner border of the eulcus it> clearly visible since it projects vent rally and posteriorly to the outer border . The lateral margin is rolled outward so that above it on the lateral faces there is a prominent depression . Viewed from the side , the dorsal line of the first thoracic segment is sinuate because of the presence of a prominent bulge behind the head . There is no coxopodal cleft or notch on the second thoracic segment . The front margin of the head is gently arched upward, with a groove behind it . fourteen ocelli. Viewed from above , it is gently arched. There are The antennae are fairly stout; the flagellum has its basal piece two - fifths as long as .the terminal; the penultimate segment is about one and a half times as long as the flagellum. The lateral borders of the second and third thoracic segments are rounded; the others are distinctly truncate and are progressively longer toward the rear . The rear border of the telson is about two - thirds as broad as the front border. (19 - Zli. Somewhat below the middle it is a little constricted The upper mid- region of the telson bulges posteriorly in a distinct triangular prominence . The external segments of the uropods 171 ar e minut e , conical , and the are a near the point of insertion is slightly raised. The internal segment is conical. The posterior faces of the uropods near the margin are provided with fine, brown spines . This species can be distinguished from other Armadillo discussed in this paper by the prominence on the tel son and the manner of pl acement of the external segments of the uropods . Locality: Mexico , Isla San Pedro Martir , Gulf of California. One specimen, the female holotype , was collected on April Z9 , 1944, by Mr. B . Osorio . Armadillo osorioi new species F igures 4Z8 - 434 This is a medium- sized specimen with a length of about 6 . 5 mm. The body is highly arched. ment. The head is set into the first thoracic seg - Viewed from above , the frontal line makes almost a straight line , being slightly convex. F rom in front , the line is also nearly straight . This margin flares slightly forward , and is not appressed to the head. The epistome is nearly at right angles to the body axis . The flagellum of the second antenna has its basal segment about a fourth as long as the terminal. Together they are shorter than the peduncle (3 9 - 45). l 72 The ocelli number thirteen in the female allotype and sixteen in the male holotype . The first thoracic segment has its lateral margin flaring outward, forming a broad oval depression above it. corners are directed slightly backward. cleft in this corner . The posterior There is a deep coxopodite This cleft proceeds forward as a shallow sulcus for less than a half of the length of the margin . The inner border of the cleft and the short sulcus are not visible from a l ateral view . posterior corner of the inner border is broadly rounded. The In the second thoracic segment at its posterior corner there is also a coxopodite cleft which is continued along the forward margin as a sulcus into which the inner border of the cleft of the first segment articulates. The lateral edge of this segment is more broadly rounded than the third and fourth . The posterior corners of the thoracic segments are slightly projected backward; the first more than the others, the last very little. The posterior portion of the second to seventh thoracic segments are only slightly raised above the anterior portion which slides under the rear of the preceding segment. The general color above is a purple - gray with whitish markings on the dorso - lateral sides over the points of muscle attachments. lar markings occur on the bead. The mouth parts project forward and ventrally. Simi- 173 When the animal is somewhat curled up , the exposed portion of the first two abdominal segments are as long as the others , though their lateral margins do not project to the sides . The exposed portion of the tel son is broader than long (14 - 11 ); its posterior border is about equal to the length. It is constricted below the middle ; its narrowest region is less than the length (9- 11 ). The uropods ar e much longer than broad; the width of the rear border ie more than twice the length of the lateral border (7-3) , and is about equal to its medial border. inner margin. The external branches are minute, set along the The inner branches are also minute . ders are oblique . The anterior bor - The under parts of the animal are unpigmented. The leg s are s l ender . Locality: Mexico . Cueva Acuitlapan , Guerrero . Male holotype and paratype were collected by C. Bolivar and B. Osorio, Bustemante, N . L . Cueva P almito , Several paratypes were coll ected by C. Bolivar , F . Bonet, B . Osorio and D . Pelaez . Armadillo murina (Brandt) , 1833 No specimens of this species came to the attention of the author in collections of isopods from Mexico. Van Name indicates a specimen from Guanajuato , M exico , reported by de Bo1·re (1886) . While 174 this species is widely distributed o ver the tropical world , no other records of this species is known for Mexico. Va n Name (1936) writes: " A s in the case of ma..,iy other well known species , the descriptions and illustrations thus far published leave much to be desired . It may be recognized by the reduction of the coxopodite ridge to a slight projection near the rear end of the segment, well removed from the margin , and the conspicuous manner in which the epimeral ends of the segments , especially those of the first dorsal and the abdominal ones , bend or flare outward, though there is no distinct groove or furrow marking off the border of the first dorsal segment. The dorsal surface appears smooth (minutely granular on magnification) in spite of the presence of slighUy raised confluent tubercles on the lateral regions of the back. Color of upper parts varies from light or dark gray to brownish or brown, with small yellowish markings on the tuberculated areas. E xposed parts of basal segments of uropoda and terminal part of telson yellow to yellowish. Usual length not over IO or lZ mm. " This spec i es was not included in the key to the Armadillo of Mexico since there were no specimens available from that country. Its description as giv en abo ve seems to relate it to Ar m adillo oaxacana n. sp., but this species lacks the confluent tubercles on the back and has a more distinctive coxopodite sulcue than in Armadillo murina . 175 Locality: Guanajuato , M exico (de Borre) 188 6 . Armadillo cacahuamilpensis B ilim ek, 1867 This animal is known 011ly from the description given by Bilimek. Some question is raised regarding its correct placement. His description (partly in Latin and partly in German) states that the antenna is five - jointed with a three - jointed flagellum; the u ropods are thin , twice as long as they are broad. The last segment of the abdomen is constricted in the middle . The possession of three segments in the flagellum of the an tenna precludes its placement in the genus Armadillo. Richardson (1905, pp . 663 - 4) pl aced this species in the genus Sphaeroniscus , though the nature of the last segm ent of the abdomen indicates that it cannot be a Sphaeroniscus . Locality: "Under stones in cave at Cachuamilpa, Mexico. " .Specimens of Armadillo pelaezi , new species , were collected in what is believed to be the same cave (Gruta de Cacahuamilpa) by M essrs. F . Bonet, C . Bolivar, and D. P e l aesi, in 1939. However , the presence of a sulcus along the entire border of the first thoracic segment would leave doub t o f its relation to cacahuamilpensis. The fauna of the ca ve at Cacahuamilp a will need more concentrated study to determine the status of A r m adillo cacahuamilpensi s . 176 Hypothetical Species In a review of the collection s of M exican lsopoda made by various individuals , it wa B noted that there is a minimum of duplication . Likewi se in the collections made at variou s times by the author in T exas and Arizona which were the basis for two papers (Mulaik 1943, 1944), numerous species occurred in the southern region which would normally be espected to occur in adjacent area s in M exico. How - e ver, the collecting in Mexico is still far from extensive and when more specimens are accumulated, many species now known for the adjoining regions of the United States and Central America should be found. The following list of species is expected t o occur in Mexico: Tylos punctatus Holme s and Ga y , 190 9. Ligia elfersi Brandt, 18 33 . San Di ego , Calif. Corpus Christi , T exas. Trichorhina triocis Mulaik , 1942 . Hidalgo and Zapata Counties , Texas . R hyscotus texensi s (R ichardson) 1905. E dinbur g and R io Grande City, Texas. R hyscotus nasutus Budde-Lund, 1908 . Near Realejo , Nicaragua . Metaponorthus mulaiki (Van Name) 1936 . P orcellio concbus Mulaik , 1943 . Verde County, T exa s . Edinburg , Texas . E den , Concho County and Langtry, Val 177 P orcellio grandeus Mulaik, 1942 . F i v e Il'.iles east of Rio Grande City, Starr County, Texas. P orcellio alpinius Mulaik, 1942 . Nine mile s west of Alpine , Brewster County, T exas. P orcellio ragusae Dolfus 1896. Concho, Hidalgo and Starr Counties , Texas . Armadillo chamberlini (Mulaik) 1942 . Armadillo arizonicus (Mulaik) 1942. E dinburg, Texas . Nogales , Olberg and R ock Spring s , Arizona . Armadillo tanneri (Mulaik) 1942 . E dinburg , Texas . Spherarmadillo schwarzi Richardson, 1907. Globarmadillo armatus R ichardson , 1910. Guatemala . Guatemala. DISCUSSION AND CONCLUSIONS The study of Mexican lsopoda , which is as yet incomplete , precludes drawing conclusions on a number of aspects . Some infer- ences can be drawn from the present material , though some of these may have to be changed as further studies are made . The following are some of the major points which have presented themselves through this study. l. The isopods of M exico were well established perhaps as early as Cretaceous t imes. The present population is believed to be directly descended from that stock. It is suspected that during later epochs these anin1als managed to survive in isolated pockets, and it is likely that they were disturbed only to a minor degree by such cataclysmic phenomena as the periods of glaciation, which scarcely touched Mexi co. Certainly it is not inconceivable that the many caves of Mexico &erved as niches to hold a reservoir of population. Conditions in these re- mained far m ore stable than above ground. 2. A number of the common homophilic isopods believed to be of Mediterranean origin have become established in Mexico since the arri val of Europeans. In nearly every area where agriculture has been practiced, one or more species of these homophiles are found. 178 M exico 179 is not alone in having these forms. They are to be found scattered over much of the temperate and tropical land areas of the world. The most common species are Porcellio scab er, P . laevis , Armadillidium vulgare , Metoponorthu s pruinoeus, and others . 3. The cave isopods of Mexico appear to be relics of the most ancient forms . These were perhaps situated best to survi ve the vicissi- tudes of climatic changes which have occurred since the C retac eous . The loss of pigment , and the reduction or complete loss of eyes , occurs in numerous species, which indicates a convergence of characters among species isolated from one another. Mutation toward an eyeless condi- tion is suspected to occur in all species, but those occurring in caves find the energy gradient arising from lack of eyes is favorable to survival under the rigorous conditions in caves. V,;.ndel (1 943) has argued favor - ably for eyeless European cave forms on this basis . 4. The isopod fauna of Mexico will prove to be far greater in number than it now is. More effective sampling of arthropods and col - lecting over large areas will fill in many gaps in the distributional map. It is probable that the isopod fauna may number over 200 species. In such a case , it can hardly be maintained that the Mediterranean region is the center of origin of land isopods . It might be more plausible to consider the Mediterranean region a center of greatest collecting to the present. 180 5. While the collections of isopods of Mexico are still too meager to draw conclusions regarding the biogeography of the group, certain hypotheses can be made. Distributed over much of the Southe rn Hemisphere are representativ es of the genus Styloniscus, which was formerly classified in the T richoniscidae in the subfamily Styloniscinae, and the genus P atagoniscus , placed formerly in the P atagoniscidae. In 1952 Vandel synonymized the genus P atagoniscus with Styloniscus, and the latter genus bec a me the type for the family Styloniscidae. F ormerly the genus Protrichoniscus was placed in the family Trichoniscidae (sensu latu) , but the characteristic pl umose bristle associated with the triturating molar area relates it to the Styloniscidae. This family has representatives in Mexico, South America , South Africa , and Australia . This region comprise s the land masses which s ome authors consider to ha ve been a unit land mass , perhaps as late as Cretaceous times. This is the Wegenerian Hypothesis. On the other hand, the genera in the family Tricboniscidae are confined to northern Mexi co, United States, and across Temperate Eurasia. BRIEF BIBLIOGRAPHY A rcangeli , A . 19 14 . Isopod terrestri raccolti dal Prof. Silvestri nel Nord- America . Boll , Lab . Zool. Gen . Agar . Portici, XXXVI , pp. 121 - 141 , figs . 1 - 7 . 1923 . Revisi one del Gruppo degli "Japlophthalmi" Isopodi ter r estri. Archivio Zoologico . X , pp. 25 9 - 322. Tav. 7 - 8 . 192 9 . Isopodi terre stri raccolti in Cuba dal P rof. F' . Silvest ri. Boll. d . Labor . d . Zool. Agrar . D . R. Instituto Super Agrar Portici XXIII , pp. 129 - 148; 6 figs. 1930 , Contributo alla conoscenze del " Microgenton" di Costa - Rica . Boll. d . Labor d . Zool. Gen. Agrar D. R . Instituto Super. Agrar Portici XXV , pp. 82 - 9 1; l fig. 1937-1938 . Tyl os Latreillii Aud. et Sav. Suoi bioptipi , sua area di di!fusione . Boll . Mus . Zool. Anat . Comp. R Univers . T orino , XLVI , pp. 1- 15; T a v , I- VI . Barnard, K . H . 1932 . Contributions to the Crustacean Fauna of South Africa . No . 11. Terrestrial lsopoda. Annals South , ,fric . Mus., XXX, part 2 , pp. 179- 388; 80 figs . Barnes, (T . C . ) 1932. Salt requirements and s pace or i entation of the littoral Isopod , Ligia , in Bermuda. Biol. Bull , , LXII , pp. 496 - 504; l fig . Bilimek, D. Blake, C. H. 1867 . F auna der Grotto Caca huamilpa in Mexico . Zool. bot , Gesell. Vien . XVIIl, pp. 901 - 908. 193 0 . Verb . R edescription of Armadilloni s cus ellipticus (Harger) Occas . P apers Boston Soc . Nat. Hist ., V, pp. 279 - 2 84; 11 figures . with some account of its habits . 181 182 Boone, (P) L . 1920 . Description of ten new isopods. Proc . U. S. Nat . Mus. , LIV, pp . 591 - 604 , Pl. LXXXIX- XCII . 1934 . Brandt, J . F . New and rare Cuban and Haitian terrestrial Isopoda. Bull. Amer . Mus . Nat . Hist., LXVI, pp. 567 - 598, Figs. 1 - 14 . 1833 . Conspectus Monographiae Crustaceorum Oniscodorum Latreillii. Bull. Soc . Imp. Natur . Noscou , VI , pp. 171 - 193 . Budde - Lund, G . 1899 . Chilton, C. A R evision of Crustacea Iso poda Terrestria" , with Additions and Illustrations . I, Eubelum. Ent. Meddel. (2) . I , 32 p . 1901. The terrestrial lsopoda of New Z ealand. Trans . Linn. Soc . London (2), VIU . Zool . , pp. 99 - lSZ:P l. 11- 16 . 1852 . On the Classification of the Crustacea Choristopoda or Tetradecapoda. 1uneric . Jour . Sc . Arts . (2) , XIV , pp. 297 - 316 . Dana , J . D. Dollfus , A . 1885. Crustacea I sopoda terrestria per familias et genera et species descripta . Hauniae . 1896 . Sur les Crustaces lsopodes terrestres du Mexico , Bull. Soc . Zool. F rance , XXI , pp. 46 - 49, Figs . 1 - 2 . 1897 . Notes de Geographie zoologique. Les Crustacea Isopodes tresstres a grande dispersion . F euille Jeun. Natural. XXVII , pp. 205 - 212. 1899 . Sur la distribution geographique de s lsopodes terrestres dans l'Afrique septentrionale , du Senegal a Obock. Proceed. 4th International Congress Zool. Cambridge (1898), pp. 250 - 260 . Gandara, G. Hansen , H. J. 1926. Las cochinillas de la humedad (lsopoda) Mem. Soc. Soc . Ant . Alzate , Mexico. XLIV , pp . 2 8 5 - 297. 1925 . Studies on .. ·. rthropoda, II . On the comparati ve Morpholog y of the appendages in the Arthropoda . A . Crustacea. Copenhagen, 176 pages; 8 planches . 183 Hatch, Melville H . 1947. The Chelifera and lsopoda of Washington and adjacent regions . Univ . of Wash. Publ. in Biol. X , No . 5 , pp. 155 - 274 . 193 9. Herold, W. Records of terrestr ial Isopoda or sow bugs from North Ainerica . .. me r . Wddl . Nat . 21 :256-57 . 1913. Bei trttge zur Anatomic and Phy siologic einige r Landisopoden Hitutung. Secretion. Atmung . Jahrb . Abt. Anat. Ontog. pp. 456 - 526; Taf. 25 - 27 . Hol mes , S. J . , and Gay, M . E . 1909. F our new species of isopods fro m the coast of California, Proc . U. S. Nat. Mus . XXXVI , pp. 375 - 379 . figs. 1- . Ives , J . E . 1891. Crustacea from the northern coast of Yucatan , the h arbor of Vera Cruz , the west coast of F l orida , and the Bermuda Isl ands . Proc. Acad. Nat . Sci. Phila. XLIII , pp. 176 - 200 . P ls . V , VI. Ja ckson , H. G . 1926 . The Mo rphology of the Isopod Head. Part I. The Hea d of Ligia oceanica . P roceed. Z ool. Soc . London , 1926 , ll , pp. 885-911; Pl. I - IV; 11 figures texts . 1928. The Morphology of the Isopod Head. Part II . The terrestrial Isopods . Proceed. Z ool. Soc . London, pp. 561 - 595; 20 figures texts . 1926 . Woodlice from Spain and P ortugal , with an account of B enthana , a Sub -Genus of Philoscia. Crustacea. Proc . Zool. So c . London . pp. 18 3-2 0 l; Pl . I - VIII . Jeanne! , R. 1942 . La Genese des Faunes terrestres. Elements de Bio geographie . P aris , 5 13 pp. 8 pls. Kinahan, J . R . Ko ch , C . L. 1857 . Analysis of certain allied genera of Terrestrial lsopoda; with description of a new genus and a detailed list of the British species of Ligia , Philougria, P hiloscia , Porcellio , Oniscus and Armadillidium. Natur . Hist. R eview. IV , pp. 258 - 282; pl XIX-XXII . 1847. System der Myr iopoden mit den Ve reischnissen und Pe richtungen zu Deutschlands C ru stacean . Regensburg. 184 Latreille , P A. 18Z9. Le regne animal distribue d 'apres son organisation pour servie de base a l 'hi stoire naturelle des animaux et d'introduction a l 'anatomie comparee , par M . le Baron Cuvier . Nouvelle edition. Tome IV. Crustacea , Arachnides et partie des Insects. Paris . Legrand, J. J . 1943. Sur I 'e volution de certaines coaptations relatives a l'enroulement des Isopodes terrestres superieurs. Compt . Rend. A cad. &c. Paris. CCXVI, pp. Z07-Z09 . Lohmander, H . 19Z7 . On some terrestrial Isopodes in the United States National Museum . Proc. Unit . St. Nat . Mus . , LXXII , pp. 1- 18; 6 figures. Menzies, R . J . 1950 . Notes on Califor nia isopods of the genus A rma dilloniscus , with a description of Armadilloniscus coronacapitalis . Miers, E . J. Miller , M . A . 1938. 1878 . On a Collection of Crustacea , Decapoda a nd lsopoda, chiefly from South America , with description of new Genera and Species . Proc . Zool. Soc . London. pp. 653 - 679; Pl. LXVI- LXlX. 1936 . California isopods of the genus Porcellio with descriptions of a new species and a new subspecies . Univ . of Calif. Puhl. Zool., XLI , pp. 165 - 1 n . Comparative ecological Studies on the terrestrial lsopod Crustacea of the Sa n Francisco Bay Region . Univers . California Puhl. Zool. , XLUI , pp. 113 - 14Z; 3 figures . Milne - Edwards , H . 1834- 1840 . Histoire naturelle des Crustaces (Suites a Bufdes fon) . Paris, Tome I , 1834; tome III, 1840 . Monad, T . 19ZZ . Sur un essai de classification rationnelle des Isopodes. Bull. Soc. Zool. F rance , XLVll , pp. 143-140. Mulaik, Stanley and Dorothea. l 94Z. New species and records of Amer ican terrestrial isopods . Bull. Univ. Utah, XXXll , No . 6. (Biol. Series , VI , No . 7 , pp. 1-11 , F ig s . 1-70 . ) 1941-1943 . New Texas terrestrial isopods with notes on other species. Bull. Univ. Utah . XXXlV , No . 3 . (Biol. Se ries , VIII , No . l. pp. 1- 15 . Fig. 1- 36.) 185 Nusbaum , J . 1891. Beitrage zur Embryologie de lsopoden. Centralbl, XI , pp. 42-49; 6 figures . Pearse, A . S. Biol. 1911. Report on the Crustacea collected by the Univer sity o f Utah Walker Exp. in the .:.tate of Vera C ruz, Mexico. Rep . No . 13 , Michigan A cad . Sci., pp . 108 - 114 , 2 P ls. Racovitza , E . G. 1925 . Notes sure less lsopodes . 13 Mo r phologie et phylogenie des Antennes , H A . Le F ouet . li rchv. Zool. exper ., LXIll , pp. 533 - 622; fig . 159 -2 10 . 1907. lsopodes terrestres (Iere Serie) B iospeologica. I V Archiv . Zool. Exper . Gen. XXXVII, pp. 145 - 25 5; Pl. X - XX. 1908 . Remy, P. lsopodes terrestres (2 eme f.e r ie). Biospeologica. I X A rchiv . Zoo!. E xper . Gen . XXXIX, pp. 239 - 415; Pl. I X- XXIII. 1925 Contribution a l'etude de l'appareil respiratoire et de la respiration chez quelques lnve:rtebres. These Nancy. 1928. Ball o<lora Merceli n . sp. Vorticellide commensal du Crustace lsopode te rr estre , Trichoniscus (Apiloniscus) provisorius Raco vitza . Annal Parasitol. VI, pp. 419 43 0 ; 4 figures. Richardson , H 1905. A Monog1·aph on the lsopoda of North ... merica . B ull . U. S. Nat . Mus . , No . 54, 727 pages; 745 figures. f.ars , G . O. Vandel , A. 189 9. An a ccount of the C rustacea of Norway . Bergen. II . l sopoda, 19 38 . Contribution a la genetique des Isopodes du genre Trichoniscus. I. Les mutations~ et pallida de Trichoni.acus (;:,pilloniscus) elisabethae Herold, et l'origine des formes cavernicoles. Bull. biol. F rance Belgique, LXXll , pp. 121 -146 ; 3 figures. 1942. Recherches sur la genetique et la sexualite des lsopodes terrestres VIII . Les modalities de l'incubation chez les lsopodes volvationnels . Bull. Biol. F rance-Belgique , LXXVI, pp. 336 - 346; 7 figures. 186 1943 . Eesai sur l 'origine, !'e volution e t la classification des Onis coidea (Isopodes terrestres) B ull. B iol. France - Belgique. Suppl. XXX , pp. 1- 136; 77 figures . l 944. Isopodes terrestres recoltes par M. R emy, au cours de son voyage en Corse (Jui llet-septembre 1942). II. La F amille des Stenoni scidae B. - L . A rchi v. Zool. Exper . LXXXIV . Net R , pp . 23 - 47; fig . 1- XXVI. . 1945 . La Repartition Geographique de s Oniscoidea . (C rustaces l s opodes terreetres) Bull. Biol. F rance-Belgique. LXXLX, no . 4, pp. 222 - 272. Fig. 13 . 1947. Su r la Genetique et l a sexualit e des isopodes terres t res. X. - E tude dee garnitures chromosomiques de quelques especes d'Isopodes ma rins dulcaquicoles et te r restres . Bull . Biol. F rance - Belgique . LXXXI , No. land 2 , pp. 155 - 1"/6. Va n Na me, W . G . 1936 . The llnierican Land and F resh - Water Isopod C ru s tacea. Bull. ..', meric . Mue . Natur Hist . LXXI , pp. 1-53 5; 323 F ig. 1940 . A supplement to the American land and fresh water iso p od Crusta cea. Bull. . . mer . Mus. Nat . Hist. 77 : 109142, 32 fig. 1942 . A second supplement to the ,l me rican l a nd and ire sh water i sopod Crustacea. Bull . ,~mer . Mu s . Nat . Hist . 8 0 :288 - 329 . Verhoefi, K. W. 1917 . 190 7 . Ueber lsopoden. 1() . -.uisatz . .~tizungsber. Ges s ell . Natur f. F reunde. Berlin, pp. 2 2 9 - 281. Ueber augenlose A rmadillidien und kritis che P r ufung der .l,~amilie Armadill idiidae. 25 Isopoden - Aufsatz . A rchi v. f. Naturgesch. LXXXIII , pp. i60 - 170 , 6 fig. 19 17a. Z ur Kenntnis der --tmung und der --tmungsorgane der l s opoda Oniscoide«. Uebe r lsopoden. 20 . _, ufsatz . Biol. Z entralbl. XXXVII, pp . 113 - 127. 187 l917b . Zur Kenntnis der E ntwicklung der Trachealsystem und der Untergattungen van P orcellio und Tracheoniscus. Ueber lsopoden 22 . Aufsatz . 0itzber, Gesel. Natur forsch . F reunde. Berlin, pp. 195 - Z23; 7 figures . 1920 . Ueber die .",tmung der Landa s seln, zugleich ein Beitrag :,,ur Kenntnis der Lntstehung der Landtiere . Ueber lsopoden. 21 , ,ufsatz. Z eit . wiss . Z.ool. , CXVlll, pp. 365 - 44 7; Taf. Vll - Vlll; 1 figure texte . 1936. Ueber lf.opoden der Balkanhalbinsel , gesammelt von Hern Dr. lw. Buresch. ill. Teil . 58 . I sopoden - Aufsatz . Mitteil. K. Natur - wiss. Inst . Sofia , I X, pp. 1- 27; 30 figu r es. 1938. Weltstellung der lsopoda terrestria, neue F amilien derselben und neus System. Zool. Jahrb. Abt . .System. OEkol. Geogr LXXI , pp. 253 - 264. 1941a Zur Kenntnis sudamerikanischer Oniscoideen. 7 l. lsopoden Aufsatz. Zool. 1\nz. CXXXIII, pp. 114-126; 15 fig. 1941b. Grundlagen zur Beurteilung der geographischen Ve rbreitung der Land. lsopoden und uber dere11 Fauna im westnorischen Gau . Zeit Morphol Okel. XXXVll , pp. 105 - 125; 7 fig . Vivo, Jorge A . V. egener , A . 1943 . Loa Limites Beogeograficos en America y ion Zona Cultur a M e5oa1nexicana. Revista Geografica, Tome III , Num 7, 8y9 , p. 109 -1 ~ 1937 . La Genese des Continents et des Oceans. 2.36 pp. 63 fig . P aris, LIST OF FIGURES Tylos latreillei, fig. l, left mandible; fig. Z, carpus of leg VU; fig. 3, epimera of segment IV; fig. 4, epimera of segment VU. Tylos niveus, fig. 5, teeth of maxilla I; fig . 6 , left maxilliped; t fig. 7, epimera of segment VII; fig. 8, carpus of leg VII; fig . 9, epimera of segment I V . Ligia baudiniana, fig . 10, posterior corner of last thoracic segment , ventral view; fig . lZ, left mandible; fig . 13 , left maxilliped;fig. 15, right mandible. Ligia exotica, fig. 11, tip of leg VII; fig . 14 , right maxilliped; fig. 16 , tip of left mandible. ., u 6 7 11 13 14 16 Ligia baudiniana, fig . 17, right maxilla I ; fig . 19, left rear corner of last abdominal segment. Ligia exotica, fig . 18; right rear corner of last abdominal segment. Ligia baudiniana, fig. 19, left rear corner of last abdominal segment. Ligia occidentalis, fig . 20, rear corner of last thoracic segment, ventral view. Protrichoniscus chica, fig . 21, carpus of leg Vil; fig. 22, distal part of leg VII; fig. 23, antenna I; fig . 24, left maxilliped; fig . 25, flagellum of second antenna; fig. 26, distal part of leg VII. Protrichoniscus bridgesi, fig. 27 , left mandible; fig . 28, second antenna; fig. 29 , first antenna; fig 30 , outer branch of right maxilla; fig. 31, inner branch of right maxilla ; fig. 32, left uropod; fig . 33, right maxilliped. ~23 5. 30 ) 27 31 32 . . b 33 b • j Protrichoniscus bridgeei (cont. ) fig . 34, leg VII; fig . 35, detail of distal part of leg VII of mal e; fig . 38 , leg I of male. Protrichoniscue palmitus , fig . 39, Leg VII of female; fig. 40, left mandible; fig . 41, telson of female; fig. 42, maxilliped; fi g. 43, first antenna; fig . 44, por tion of uropod; fig. 45, leg I of female; fig . 46 , right mandibl e; fig . 47, inner branch of maxilla I; fig . 4 8 , outer branch of maxilla I . Cuevoniscus yucatanus , fig . 49, mandible; fig . 50 , dorsal view of head and right antenna II; fig. 55, telson. 40 00 q ,. ] 1~. 49 44 55 50 Cuevoniscus yucatanus (cont . ), fig. 51, distal part of leg Vll of male; fig . 52, antenna I; fig . 53 , outer branch of maxilla I; fig. 54, uropod. Cuevoniscus balamus , fig . 56, Leg Vll of male; fig. 57, detail of tip of leg VII; fig. 58 , antenna I. Cuevoniscus grutus, fig . 59, right mandible; fig. 60, uropod; fig. 61, inner branch of maxilla I , fig. 62, leg Vll; fig . 63, outer branch of maxilla I, fig. 64, antenna I. Trichoniscus cruzius, fig . 65, left mandible; fig . 66, inner branch of maxilla I; fig . 67, oute r branch of maxill a I; fig . 67, outer branch of maxilla I; fig . 68 , part of leg VII of female; fig . 69, flagellum and penultimate segment of antenna I; fig . 70, uropod of female showing detail near tip. Trichoniscus cruzius (cont . ). fig. 71, maxilliped; fig. n,. leg VII of male; fig . 73, first pleopods of mal e . Trichoniscus orchidicolis, fig. 74, antenna I; fig . 75, dorsal view of anterior part of body; fig. 76, leg VII of femal e; fig . 77, antenna II; fig . 78, leg I of female; fig . 79, dorsal view of rear of body . Trichoniacus hoctunis, fig . 80, leg I of male: fig 81, detail of distal part of leg I . Haplophthalmue danicus, fig . 8Z, uropod; fig. 83, outer branch of maxilla I; fig . 84, left mandible; fig. 85, antenna I; fig . 86, flagellum of antenna II. Stenoniscus quintana, fig . 87, uropod, ventral view; fig . 88 , pleopod; fig. 89, lateral view of animal; fig. 90, leg VII, distal part; fig. 91 , ventral view of abdomen; fig. 9Z, dorsal view of animal. 82 85 86 ~ ~ --;;- ~ 91 Armadilloniscus holmeai, fig 93, dorsal view of head and first thoracic segment; fig . 94, dorsal view of abdomen; fi g . 95, outer branch of maxilla I; fig . 96, antenna II; fig. 97, distal part of leg VII; fig. 98, inner branch of maxilla I ; fig . 99, second maxilla showing inner and outer branches; fig. 100, left mandible; fig. 10 1, right mandible; fig . 102, distal part of leg IV; fig . 10 3, region of the telson and uropod; fig. 105 , distal part of leg I. Rhyscotus colimaris, fig. 106, distal part of antenna I; fig . 107, distal view of rear of body; fig. 108, uropod; fig. 109 , dorsal view of hea d and first thoracic segment. Rhyscotus laxus, fig. 110, antenna II; fig. 111, fir st pleopod; fig. 11 2, uropod. 93 95 . fl) lO? f··~ 109 ' ll2 Rhyscotus laxus (cont.) , fig. 113, outer and inner branch of maxilla I; fig. 114, right mandible; fig , 115, male pleopod I. Trichorhina xoltuma, fig. 116 , dorsal view of head; fig, 117, clae of leg VII; fig. 118, pleopod I; fig. 119, leg VII; fig. 120, maxilliped; fig . 121, various spines along rear border of first thoracic segment; fig. 122, tip of antenna II; fig . 123 , dorsal view of abdomen of male; fig . 124 , antenna I; fig . 125, dorsal view of rear of abdomen of female; fig. 126 , right mandible. Trichorhina atoyaca , fig, 12 7, maxilliped; fig. 128, antenna I; fig. 129, left mandible; fig, 130, right mandible . Trichorhina zimapana, fig , 131, left mandible; fig, 132, inner branch of maxilla I; fig. 133, outer branch of maxilla I; fig . 134 , antenna I; fig . 135 , distal end of maxilla II; fig . 136, male pleopod I. 116 '! / I ' / 120 121 12 2 119~ 131 n~ ' - ) - / ~ 132 ) 33 184 135 186 Trichorhina zimapana (cont.), fig. 137, uropod; fig. 138, leg Vil; fig. 139 , detail of dactylis VII; fig. 140, male pleopods II; fig. 141, maxilliped; fig. 142, leg Vil; fig . 143, detail of tip of male pleopod; fig. 144, ventral view of lateral part of first dorsal thoracic plate; fig. 145, leg I. Trichorhina gorgosa, fig . 146 , tip of leg I of female; fig. 147, tip of leg VII; fig . 148, tip of abdomen; fig . 149 , details of spine arrangement on posterior and on lateral borders of first thoracic segment; fig. 150, ventral view of head. Trichorhina s quamata (figures after Verhoeff), fig. 151, posterior of abdomen; fig . 152, antenna II, fig . 153, fanshaped spines along posterior margin of first thoracic segment; fig. 154, right mandible; fig . 155, male pleopods; fig. 156 , tip of maxilla I, outer branch; fig. 157, tip of left mandible . Trichorhina piebalda, fig. 158, antenna l ; fig. 159, left mandible; fig. 160, tip of male pleopod. Trichorhina p i ebalda (cont . ). fig. 161, outer branch of maxilla I; fig . 162 , right mandible of male; fig. 163, inner branch of maxilla I , fig . 164, maxilliped; fig. 165, uropod of male; fig. 166, maxilla II; fig. 167 , eye area; fig . 168, leg VII of male; fig . 169, tip of male antenna; fig . 170, several spines on fir st thoracic segment; fig . 171 , antenna I of male, showing detail of a spine on tip of pedicel; fig . l 72 , male pleopod I. Alloniscus perconvexus , fig . 173 , male pleopod; fig . 174, tip of leg VII of male; fig . 175, uropod; fig. 176 , maxilla II, fig. 177, medial view of right mandible; fig . 178, left mandibl e; fig . 179, tip of antenna II; fig. 180, maxilliped. <l ~179 177 Oniscus asellus, fig . 181, mandibl e; fig . 182 , antenna 11; fig. 183 , inner branch of maxilla I; fig . 184, maxilliped; fig. 185 , tlp of leg VII. Hoctrmus murcielago , fig. 186, uropod; fig. 187, dorsal view of head; fig. 188 , male uropod I; fig. 189, male uropod II; fig. 190, maxillipcd; fig . 191, mandible; fig . 192, inner branch of maxilla I; fig . 193, leg I of male; fig. 194, maxilla I, outer branch; fig. 195, leg VII. Philoscia colima, fig. 196, mandible; fig . 197, antenna II; fig . 198, arrangement of ocelli showing spines among them; fig . 199, maxilliped; fig . 200, outer branch of maxilla I fig. 201, pleopod I of female; fig. 202, uropod; fig. 203, leg I of female; fig . 204 , tel son; fig. 205, maxilla I , inner branch. , ~ 187 \_) \d 194 197 m ~ 98 / 188 P hiloscia colima {cont . ), fig. 206, view of head; fig. 207, leg VII. Philo aci a vera, fig. 208, antenna I; fig. 2 09, ma.xilliped; fig. 210, mandible; fig. 21 1, outer branch of maxilla; fig 2 12, leg I; fig. 213, telson of male; fig. 214, antenna II. Philoscia icacosa, fig. 215, leg I of female; fig. 216, maxilliped. Philoscia richardsoni, fig. 2.17, uropod; fig. 2.18, outer branch of maxilla I; fig. 219, inner branch of maxilla I; fig. 220, antenna I; fig, 2.21, antenna I!; fig. 22.2, leg VII of female; fig. 223, right mandible . Philoscia kanaba, fig. 2.24, leg VII of male; fig. 225, outer branch of maxilla I; fig. 2.26, details of spines on carpus of leg VII of male; fig. 2.2 7, flagellum of antenna II; fig. 228 , mandible; fig. 229, leg I of male. 1S::1 213 218 229 Ph.iloscia kanaba (cont.), Philoscia hermosa , fig. Z30, maxilliped of female . fig. Z31, outer branch of maxilla I; fig. ZJZ, outer branch of maxilla 11; fig. Z33, distal portion of antenna II; fig . Z34, leg VII; fig . Z35, leg I of male; fig . Z36, region of right eye ; fig. Z37, antenna I; fig . Z38 , right mandible . Philoscia contoya, fig. Z39, outer branch of maxilla II; fig. Z40 , uropod; fi g . Z41, maxilliped; fig . Z4Z, inner branch of maxilla I; ,fig. Z.43, outer branch of maxilla I; fig. Z44, leg VII; fig. 245, mandible; fig. Z46 , pleopod I of f emale; fig . Z.47, antenna II; fig . Z48 , leg VI Cylisticus conv exus, fig. 249, outer branch of maxilla I; fi g . Z.50 , leg I; fig . Z.51, inner branch of maxilla I; fig. Z5Z, flagellum of antenna II; fig . Z53, maxilliped. C) 232 253 Nagara cristata , fig . 254, maxilliped; fig . 255 , dorsal view of head; fig. 256 , mandible; fig . 257 , uropod; fig. 258 , leg I of female; fig 259 , antenna I; fig . 260, tip of antenna II. Trachelipus richardsoni, fig. 261, left mandible; fig. 262, right mandible; fig. 263 , inner branch of maxilla I; fig. 264 , outer branch of maxilla I of the male; fig. 265, outer branch of maxilla I of female; fig. 266, tip of flagellum II; fig . 267, maxilliped; fig. 268, uropod; fig. 269 , male pleopod II; fig . 270 , male pleopod l; fig . 271 , antenna 11; fig . 272 , tip of maxilla II; fig. 273, pleopod I of female; fig . 274, dorsal view of front part of body; fig. 275, dorsal view of rear part of body; fig . 276, leg I of male. Porcellio scabrosa, fig. Z77, dorsal view of head; fig. Z78, leg I of male; fig . Z79, leg VII of male; fig . ZSO, dorsal view of rear of abdomen. P orcellio marginali, fig . Z8 l, uropod; fig . ZSZ, tip of male pleopod I; fig . Z83, female pleopod l ; fig. Z84, maxilliped; fig. Z85, female pleopod II. Porcellio scaber, fig. Z86, maxilliped; fig . Z8 7, male pleopod IV; fig. Z88, outer branch of maxilla I; fig. Z89, inner branch of maxilla I; fig. Z90, outer branch of maxilla II; fig. Z91, antenna I. Porcellio laevis, fig . Z9Z, flagellum of antenna II; fig. Z93 , maxilliped II; fig. Z94, mandible; fig . 295, maxilliped; fig . Z96, epipharynx; fig. Z97, outer branch of maxilla I; fig. Z98, inner branch of maxilla I . Metaponorthua pruinosus, fig. Z99, inner branch of maxilla I; fig. 300, outer branch of maxilla I 280 284 Q 185 289 290 298 297 292 Metaponorthus pruinosus (cont.), fig . 301 , mandible; fig. 30Z , distal portion of leg VII; fig. 303, maxilliped. Metaponorthus virgatus , fig . 304, outer branch of maxilla I; fig . 305, inner branch of maxilla I; fig . 306 , antenna I; fig . 307, maxilliped; fig. 308 , merus and carpus of leg VII of male; fig. 309 , distal part of leg VII of male; fig. 310 , male pleopods I ; fig. 311, ma.le pleopod I V; fig. 31Z, tip of maxilla II; fig. 313, telson; fig. 314 , uropod. Metaponorthus ixma, fig. 315, outer branch of maxilla I; fig. 316, mandible; fig . ~17 , maxilliped; fig . 318 , uropod; fig. 319, inner branch of maxilla I. Metaponorthus saussurei, fig. 3ZO, view of rear of abdomen; fig. 3Z 1, lateral portion of anterior part of body. 804 08 805 I 806 821 Armadillidium vulgare, fig . 32Z , outer branch of maxilla I; fig . 3Z3 , inner branch of maxilla I; fig. 324, maxilliped; fig . 3Z5, uropod. Spherarmadillo huatusco , fig. 3Z6, dorsal view of rear of abdomen; fig . 3Z7, medial view of uropod; fig. 3Z8 , antenna II; fig. 329, Leg I of female; fig . 330, maxilliped; fig . 331, outer branch of maxilla I; fig. 33Z , ventral view of head; fig. 333, maxilla I. Spherarrnadillo cuevicola, fig. 334, ventral view of sulcus on first thoracic segment; fig. 335, antenna I; fig. 336, lateral view of body of male; fig. 337, front view of head; fig . 338, leg I ; fig. 339, view of the body from the rear; fig. 340 , distal part of antenna II; fig. 341, maxilliped. ./ I 824 825 330 837~ ... \ ' ~ " M' Scleropactes cedrosa, fig. 34Z, dorsal view of head; fig . 343 , leg VII; fig. 344, ventral view of abdomen; fig . 345 , maxilliped; fig. 346, outer branch of maxilla I . Armadillo junglaoris, fig . 347, ventral view of anterior part of body; fig . 348, dorsal view of rear of body; fig. 349 , ventral view of lateral margins of first and second thoracic segments; fig . 350, ventral view of uropods and telson; fig. 351, lateral view of front part of body. Armadillo minutus, fig. 35Z, l ateral view of left margins of first two thoracic segments; fig . 353, dorsal view of abdomen; fig . 354, posterior view of abdomen; fig . 355 , front view of the head. Armadillo b olivari, fig . 356, dorsal view of anterior part of body; fig. 357, ventral view of uropods and telson; fig . 358, maxilliped. 34 9 35 ~ 35 5 35 6 357 85 8 , crmadillo minutus (cont), fig . 359, dorsal view of abdomen; fig. 360, rear view of abdomen; fig . 361, antenna II. Armadillo acapulcocolis, fig. 362, dorsal view of female: fig. 363, posterior view; fig. 364, ventral view of rear; fig . 365, ventral view of head region . Armadillo benetisla , fig. 366, view of posterior of abdomen of male; fig. 367, maxi.lliped; fig . 368, rear view of female; fig. 369, uropod; fig . 370 , ventral view of lateral margins of first and second thoracic segments; fig . 371 , lateral view of front of body; fig. 372, front view of head. Armadillo stuckchensis, fig. 373, front view of head; fig. 374, ventral view of uropods and telson; fig . 375, leg I of male. ·~ 36 0 86 3 -- -- -, 37 1 36 9 86 8 Armadillo stuckchensis (cont.), fig . 376, posterior view of abdomen; fig . 377, lateral view of first thoracic segment; of male; fig. 378, lateral view of abdomen; fig. 379, details of carpus of leg I 0£ male . Armadillo boneti, fig . 380, ventral view of head region; fig. 381, lateral view of whole animal; fig. 382, dorsal view of head region; fig. 383, view of posterior of body from the rear; fig. 384, view of head region from in front; fig. 385, ventral view of margins of first two thoracic segments . Armadillo walkeri, no figures. Armadillo pelaezi, fig. 386, maxilliped; fig. 387 , outer branch of maxilla I; fig . 388, female pleopod Il; fig . 389, female pleopod I; fig. 390, medial view of uropod; fig. 391, posterior view of telson; fig. 392, dorsal view of animal; fig: 393, ventral view of lateral margins of first three thoracic segments; fig. 394, front :view of head; fig. 395, leg I; fig. 396, detail of tip of leg I; fig . 397, ventral view of telsor. and uropods. Armadillo pelaezi (cont. i, fig . 398, lateral view of front part of animal; fig . 399, lateral view of rear of animal; fig . 400, posterior view of abdomen. Armadillo colimaris, fig . 401 , front view of head; fig. 402, posterior view of abdomen; fig. 403 , front view of head. Armadillo mexicana, no figures. Armadillo soyatlanis, fig . 404, posterior view of abdomen; fig. 405, dorsal view of front of body; fig. 406, ventral view of margin of abdomen; fig. 407, ventral view of head region; fig . 408, lateral view of animal; fig. 409, dorsal view of rear of animal. Armadillo schultzei, no figures. Armadillo oaxacana, fig . 410 , ventral view of head region; fig. 411 , dorsal view of posterior of body; fig . 412, ventral view of lateral margins of first two thoracic segments. Armadillo oaxacana (cont.), fig. 413, tip of maxilliped; fig. 414, dorsal view of front of body. Armadillo dugesi, no figures. Armadillo articulata, fig. 415, ventral view of lateral margin of the left side of the body; fig. 416, mandible; fig. 417, posterior view of rear of abdomen; fig. 418, dorsal view of body; fig. 419, ventral view of head region; fig. 420, maxilliped; fig. 421, outer branch of maxilla I; fig. 422 , lateral view of posterior of body. Armadillo martira, fig. 423, posterior view of rear of body; fig. 424, dorsal view of front of body; fig. 425, ventral view of margin of abdomen; fig. 426, lateral view of head region. Armadillo martira (cont.) , Armadillo osorioi, fig. 427, front view of head region . fig. 428, front view of head; fig. 42 9, posterior view of rear of body; fig. 430, maxilla I, inner and outer branches; fig . 431, male pleopods II; fig . 432, lateral view of front of body; fig. 433 , mandible; fig. 434, ventral view of posterior corner of first thoracic segment. Armadillo murina, no figures. Armadillo cacahuamilpensie, no figures . • ( 431 430 ' ' '' . . 434 433