17286893 glyptodonts of north america

8/6/2019 17286893 Glyptodonts of North America

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FRONTISPIECE.-Reconstruction of Glyptolherium anzonae.


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S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Y N U M B E R 4 0

G l y p t o d o n t s of N o r t h A m e r ic aDavid D. Gillette

andClayton E. Ray

ISSUEDDEC 2 11 98 1SMITHSONIAN PUBLICATIONS

S M I T H S O N I A N I N S T I T U T I O N P R E S SCity of Washington

1981


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C o n t e n t sPage

vrefaceI n t r o d u c t i o n 1Previous W ork 3Sys temat ics 5Subfamily GLYPTODONTINAE 10

G e n u s Glyptothenum O sb orn . . 10Glyptothenum texanum O sbor n . 11Glyptothenum anzonae Gidley 12Glyptothenum flondanum ( S i m pson) , new com bi na t i o n 14Glyptothenum cylindncum (Brown) , new com bin at io n 15Glyptothenum mexicanum ( C ua t apa r o and R am i r ez ) , newcom bi na t i on 16

Dis t r ibut ion 18Osteology 27

Skull 27Pres acra l Axial Skeleto n 68Fr on t L i m b 81Pelvis 112H i n d L i m b 124C a u d a l V e r t e b r a e 162C ar apace 168C a ud a l A r m or 194

Selec ted Aspects of Gly pto don t Pa leobiology 199Fun c t i ona l Mo r pho l ogy 200H ab i t a t 207Evo l u t i ona r y H i s t o r y o f Glyptothenum 208

Conclus ions 209A p pen d i x : Tab l e s o f M easur e m e n t s 212Li t e r a t u r e C i t ed 252

m


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W e respect fu l ly d edica te the present mon ogr aph to the la te T ed Ga lush a ,whose expert f ield work made this revision possible.


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Pre face"Mot he r , " he sa i d , " t he re a re t wo ne w an i mal s i n t he woods t oday , and t he one t ha t you

sa i d c ou l dn ' t swi m, swi ms , and t he one t ha t you sa i d c ou l dn ' t c u r l up , c u r l s ; and t he y ' ve goneshares in the i r pr ickles , I th ink, because both of them are scaly al l over , instead of one be ingsmooth and the other very pr ickly; and besides that , they are rol l ing round and round in c i rc les ,an d I do n ' t fee l com fy."

"So n , son , " sa id M ot h e r Ja gu ar e ve r so ma ny t i me s , g rac i ous l y wa v i ng he r t a i l , "a He dge hogis a He dg e hog , an d c an ' t be any t h i ng bu t a He d ge ho g ; and a T or t o i se i s a T or t o i se , an d c anne ve r be any t h i ng e l se . "

"But i t i sn ' t a Hedgehog, and i t i sn ' t a Tor toise . I t ' s a l i t t le b i t of both , and I don ' t know i t sp r o p e r n a m e . "

"N ons e nse ! " sa i d Mo t he r Ja gu ar . "E v e ry t h i ng has it s p rope r nam e . I shou l d c a ll it 'Arm adi l lo ' t i l l I found out the real one . And I should leave i t alone."Rudyard K i p l i n g , " T h eBe g i nn i ng o f t he Armad i l l o s"

Had Kipl ing chronic led the Ple i s tocene ins tead of modern t imes , he nodoubt would have passed over the armadi l los in th i s parable for the even morebizar re g lyptodonts . For these ext inc t c rea tures of the pas t outwardly resembled mod ern arm adi l los and tur t l es , an d ecologica l ly perha ps represented anan i m a l som ew her e be tw een a l and t o rt o is e and a h i p pop o t am us . J us t a sa r m ad i l l os t oday a r e am ong t he s t r anges t o f m am m al s , t he g l yp t odon t s o f t hePle i s tocene , represent ing a branch of the same order , present a perplexingcombinat ion of unl ike ly charac ters . I f the i r foss i l remains had gone undiscovered , g lyptodonts could only have been the product of a poet ' s imaginat ion,for their very existence could never be predicted within the confines of modernsc ience and l og ic . Th e i r i m pr ob ab l e ex i s tence no t w i t hs t and i ng , g l yp t odo n t scom pr i sed an i m p or t an t sou t he r n g r oup of cha r ac t e r i s t ic N or t h A m er i canm am m al s o f t he P l e i s t ocene Epoch . They w er e l a r ge and cum ber som e ,dwa rf ing the la rges t of m od ern arm adi l los . In man y respects the i r a na tom yref lec t s ext reme adapta t ion for mass ive bui ld and heavy weight . They haveno l iv ing counterpar t s , except wi th in our poet ic imaginat ion. Pic ture , i f youwi l l , a g iant tor to i se as a mammal , behaving as a lowland herbivore , wi thkinship to a rmadi l los and the ext inc t ground s lo ths . Such are the g lyptodonts ,the Nor t h Am er ica n represen ta t ives of which are reviewed here .


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G l y p t o d o n t s of N o r t h A m e r i c aDavid D. Gillette

and Clayton E. Ray

Introduct ionT he ex t inc t g r oup o f eden t a t e s com m o nl y

ca l l ed "g l yp t odon t s " ( G r eek : "ca r ved t oo t h" o rfree ly , "grooved tooth") has perplexed s tudents ofnatural history since their discovery early in the19th century . These former occupants of the NewWorld t ropics and subt ropics combine an unl ike lyar ray of chara c ter i s t i cs usual ly cons idered un iqu et o o t he r ve r t eb r a t e s . T he p r edo m i n an t f ea t u r e istheir tur t le- l ike shel l , or carapace (Figure 1) . Differ ing f rom the typica l a rmadi l lo a rmor by beingalmost ent i re ly immobi le , the g lyptodont carapace afforded excellent protec t ion. A t ten da ntspecial izat ions in the axial skeleton are convergent wi th chelonian anatomy: extens ive fus ion ofmost of the vertebral column and fusion of thepelvic g i rd le to the carapace , render ing the pe lv i sen t i r e l y i m m obi l e .

The g lyptodont dent i t ion resembles in i t s cons t ruc t ion tha t found in cer ta in rode nts , notablym i c r o t i nes and capyba r as . B u t g l yp t odon t t ee t hlack enamel , as do those of o ther edenta tes , andglyptodonts a l so lack inc i s i form and canini formteeth . Glyptodont cheek tee th are the "most hyp-sodon t " and t he "m os t homodont" am ong t e r r e s t r i a l m a m m a l s .

The g lyptodont skul l has modi f ica t ions notDavid D. Gillette, Shuler Museum of Paleontology, Department ofGeological Sciences, Southern Methodist University, Dallas, Texas75275. Clayton E. Ray, Department of Paleobiology, National Museum of Natural H istory, Smithsonian Institution, Wash ington, D. C.20560.

found i n o t he r m a m m al i a n sku l ls . T he bonessu r r ound i ng t he den t a l ba t t e r y ( m ax i l l a , pa l a t ine ) a r e ve r ti ca ll y expand ed t o acc om m o da t e t hepecul ia r dent i t ion , whi le bones of the bas icran-ium are brachycephal ic . The skul l roof was protec ted by an ar t i c ula te d se t of de rm al bo nes or"cepha l i c sh i e l d . " We p r opose t ha t t he r e w as alarge fleshy snout or a proboscis s imilar to thatfound in e lep han ts , t ap i r s , an d p yroth eres .

T h e legs , especia lly the h ind l imb , a re e le ph ant i ne . G l yp t odon t s su r pas s t he p r obosc i dean p r o por t ions c lass ica l ly i l lus t ra ted as gravipor ta l andr ep r esen t one o f t he "m os t g r av i por t a l " g r oupsever to have l ived. Thei r l a rge ta i l probablyfunc t ioned a s a cou n t e r b a l anc e i n locom ot i on , asan acc om m od at io n for the lack of pe lv ic andax i a l m ob i l i t y . The cauda l ve r t eb r ae o f t he N or t hAmer ican representa t ives were encased in comple te a r t i cula t ing r ings of bony scutes . Despi tesome recons t ruc t ions for Nor th Amer ican g lypt odon t s show i ng an e l abor a t e t e r m i na l m ace , t h i scons t ruc t ion i s found only in some of the i r SouthAmer ican re la t ives . Ins tead , the t a i l of Nor thAmer ican representa t ives ended in a b lunt t e r minal tube formed by the fusion of two or threecaudal r ings .

Class ica l ly inc luded as members of the ext inc tP l e i s t ocene m ega fauna , g l yp t odon t s r eachedNor th Amer ica re la t ive ly la te in the h i s tory of thefami ly . Al ready divers i f i ed and widespread inSouth Amer ica in the Miocene , i t was a t the c loseof the Pl iocene Epoch or perhaps in the ear l i es t


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S M I T H S O N I A N C O N T R I B U T I O N S TO P A L E O B I O L O G Y

Ple i s tocene tha t g lyptodonts f ina l ly invadedNor th Amer ica . There they exper ienced onlymodest success, surviving unt i l the Late Pleistocene. Th e North Amer ican representa t ives aredescendan t s of p r o b a b l y a single invasion of the i rSou th Ame r ican re la t ives in to Ce nt ra l Am er ica .Su bse qu ent evolu t ion from this ear ly Pleistoceneancestry resul ted in the North Amer ican speciesreviewed in the present s tudy.

Ecologica l ly , g lyptodonts indica te t ropica l orsubt ropica l habi ta t s , wi th quie t or s t and i ng w a t e rand dense , lush vegeta t ion. These requi rementsare indica ted by t he i r ana t om y, d i s t r i bu t i on ,faunal associat ions, an d geologic occurrences.

A l t hough p r esen t in only a few N or t h A m er i can Pleistocene faunas, wherever they exist glypt odon t r em a i ns are not likely to be over looked,for the scu t e s com pr i s i ng t he i r ca r apace num bersom e 1800 or m o r e per i nd i v i dua l . O nce a paleontologist has seen an i so la ted g lyptodont scute ,he or she is unlikely to forget its cons t r uc t i on ;scutes a re unmis takable and can scarce ly be identified as be l ong i ng to any o t he r o r gan i sm .

Nor th Amer ican g lyptodonts , previous ly referred to as m a n y as five genera, are here inassigned to one genus , Glyptothenum, an d five species, G. texanum, G. arizonae, G flondanum, G cylin-dncum, an d nom i na l l y , G. mexicanum. U nt i l now,classification of N or t h A m er i can g l yp t odon t s hasbeen largely inferent ial , as m at e r i a l has beengene r a l l y i nadequa t e to establ ish credible taxonom i c a s s i gnm ent s .

T h r o u g h the courtesy of the D e p a r t m e n t ofV er t eb r a t e Pa leon t o l ogy , A m er i can M useu m ofNatura l His tory , severa l excel lent g lyptodontspecimens f rom Ar izona , previous ly unrepor ted ,p r ov i ded a sol id foundat ion for the present review. This col lect ion includes several completeand nea r l y com pl e t e ca r apaces , one of w hi ch isassociated with a near ly comple te skele ton, thefirst such recovered in N or t h A m er i ca . Thesespecimens were col lec ted under the able d i rec t ionof the late Te d G a l u s h a of t he F r i ck Labor a t o r yin the years 1938-1939, 1943, 1948, an d 1954.These A r i zona g l yp t odon t s are ident i fied as Glyptothenum texanum, r ep r esen t i ng the ancestral s tock

for at least two other Nor th Amer ican species ,a n d p r o b a b l y for two others as w el l . Wi t hou tthese specimens and the cour teous ass i s tance provided by m e m b e r s of the A m e r i c a n M u s e u m ofN at ur a l H i s t o r y , in pa r t i cu l a r t ha t of Mr . G a l u sha , th i s s tudy could never have been in i t i a ted ,much less concluded.The present review is weighted heavi ly towardosteology an d t a x o n o m y in the bel ief tha t es tabl i sh i ng adequa t e m or pho l og i ca l an d t a x o n o m i cfounda t i ons for future s tudies is of p a r a m o u n ti m p o r t a n c e .

ABBREV IATIONS.Specimens from the following inst i tut ions an d d e p a r t m e n t s h a v e b e e n exa m i n e d for t h i s r ev i ew : A m er i can Museum ofN at ur a l H i s t o r y , D epa r t m en t of V e r te b r at e Pal eon t o l ogy ( A MN H ) an d Fr ick Col lec t ion (F:AM); C h a r l e s t o n M u s e u m ( C h M ) ; M i d w e s t e r nUnivers i ty , Col lec t ion of V er t eb r a t e Fos si ls( M W U ) ; T e x a s M e m o r i a l M u s e u m ( T M M ) ;Univers i ty of Flor ida , Col lec t ion of V e r t eb r a t eFossils (UF), an d Col lec t ion of the Flor ida Geologica l Survey [UF(FGS)] ; Univers i ty of Mi ch i g a n M u s e u m of Pa l eon t o l ogy ( U MMP) ; co l l ec t ions of the former Uni ted Sta tes Nat ional Mus e u m , ( U S N M ) in the N a t i o n a l M u s e u m of N at ura l His tory , Smi thsonian Ins t i tu t ion; WestTexas S t a t e U n i ve r s i t y ( WT) , and the J o h n s t o nC o l l e c t i o n ( J W T ) .

A C K N O W L E D G M E N T S . W e are deeply indebtedfor supp or t an d assistance to m any f r i ends am ongw h o m the fol lowing deserve special recognit ion:C l au de A l b r i t t on , J r . ; Lyne t t A nder son ; C a t he r i ne C asey ; Wal t e r W. D a l ques t ; R ober t J. E m r y ;R a l p h E s h e l m a n ; the late Ted G a l u s h a ; R o b e r tHabet ler ; B i l ly Harr i son; the l a t e C l aude WH i b b a r d ; N i c h o l a s H o t t o n III; L a w r e n c e I s h a m ;K a r o li K u t a s i; J o s h u a L a e r m ; W a n n L a n g s t o n ,J r . ; Arnold Lewis ; Evere t t Lindsay; Ernes t L.Lunde l i us , Jr.; M a l c o l m M c K e n n a ; W i l l i a mMel t on ; G ar y Mor gan ; S t an l ey J. O l sen ; F r ankPea r ce , Robert W. Pur dy ; A l be r t Sande r s ; B obbSchacffer; Bob H. Sl augh t e r ; G l adw yn Su l l i van ;B er y l Tay l o r ; R i cha r d Tedfo r d ; S. D a v i d W e b b ;J o h n A. Wilson; and J i r i Zidek. We wish par t ic ular ly to t h a n k the m e m b e r s of t h e D e p a r t m e n t


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NUMBER 40 fof V e r t eb r a t e Pa l eon t o l ogy at t he A m er i can M useum of N a t u r a l H i s t o r y fo r m ak i ng ava i l ab l e t hesuperb mater ia l f rom Ar izona , which cons t i tu testhe principal basis for this s tudy. As always, theyhave been gene r ous w i t h spec i m ens , da t a , andthei r t ime. Most of hundreds of hours of de l ica telabora tory prepara t ion of these and other speci mens for th i s s tudy was done by Gladwyn B.Sul l ivan wi th unfa i l ing ski l l and good cheer . Lawrence Isham pre pa red Figures 1-4 an d 95, an d heprovided exper t advice on the prepara t ion ofi l lus t ra t ions . Bonnie Dalze l l prepared the f ront i s piece and assisted in the complet ion of some ofthe figures. We are especial ly grateful to DavidWebb , R ober t Em r y , and E l a i ne A nder son fo rcr i t i ca l reviews of the manuscr ip t . Bob Slaughterserved as a ca ta lys t in in i t i a t ing our col labora t ionand i n sus t a i n i ng i t t h r ough com pl e t i on .

Da vid Gi l le t t e ' s 1974 research was supp or te dby a Smi thsonian Ins t i tu t ion predoctora l fe l lowsh i p , a N a t i ona l Sc i ence Fo un da t i o n D oc t o r a lDisser ta t ion Improvement Grant in the Fie ld Sci ences , and a Sm i t hson i an I ns t i t u t i on Sho r t - Te r mV is itors Aw ard. We are gra teful for the op po r tuni t i es tha t these organiza t ions have provided.

Bes ides those persons and ins t i tu t ions a l readyment ioned, we acknowledge gra teful ly the ass i s t ance of adminis t ra t ion , sc ient i f i c staff, a n d s u p por t ing personnel a t the Ins t i tu te for the Study ofEa r t h and Man , Sou t he r n Met hod i s t U n i ve r s i t y ;t he Tex as M em or i a l M useu m , U ni ve r s i ty ofTexas ; Mi dw es t e r n U ni ve r s i t y , Wi ch i t a Fa l l s ,Texas ; t he C ha r l e s t on M use um ; t he N a t i ona lM useu m of N a t u r a l H i s t o r y ( Sm i t hson i an I ns t it u t i on ) ; and t he A m er i can M use um of N a t u r a lHis tory .

Previous WorkC u a t a pa r o and R am i r ez ( 1875), t w o a s tu t e

civi l engineers , were the fi rs t to report on theexis tence of g lyptodonts nor th of South Amer ica ,desc r i b i ng a com pl e t e ca r apace and a s soc i a t edskele ta l rema ins f rom the V al ley of M exico asGlyptodon mexicanus. Subsequent recover ies of Mexican g lyptodonts were repor ted by Fel ix and Lenk

(1889) , who named a new species , Glyptodonnathorsti f r om Ej u t l a , O axaca , and by B r ow n( 1912) , w ho nam ed and desc r i bed Brachyostraconcylindricus f rom A m e ca , J a l i s co , an d p r oposed t ha tGlyptodon mexicanus per t a i ned t o h i s genus . Ma l -donado-Koerdel l (1948) re jec ted Glyptodon nathorsti Fel ix an d L enk, con s ider ing i t a ju ni or synonym of Brachyostracon mexicanus. H i bba r d ( 1955)fo ll ow ed M al do nad o- K oer d e l l i n t h is r ega r d , bu the acknow l edged t ha t "un t i l t he r ange and va r i a t ion of Brachyostracon mexicanus i s known, however , the re is as m uc h jus t i f i ca t ion for recogn iz ingB. nathorsti as for recognizing B. cylindricus" ( H i b bard , 1955:51) . We recognize B. cylindricus (=Glyptothenum cylindncum) a n d , n o m i n a l l y , B. mexicanus ( = Glyptothenum mexicanum); the s ta tus of B.nathorsti (unseen) remains uncer ta in , and we a l sopr ov i s i ona l l y fo l l ow Mal donado- K oer de l l .

Brown's (1912) descript ions were the last subs t an t i a l con t r i bu t i ons on Mex i can g l yp t odon t s ,a l t hough seve r a l o t he r s have r ecor ded add i t i ona lrecover ies of g lyptodonts in Mexico (Hibbard ,1955; Da lque s t , 1961; Si lva-B arcenas , 1969;Mo oser an d Da lque s t , 1975). New ma ter ia l ofgood qua l i ty and r eeva l ua t i on o f t he nam e d Mex ican taxa wi l l be of grea t impor tance in theeven t ua l i m pr oved unde r s t and i ng o f g l yp t odon t sfound in the Un i ted Sta tes , which form the pr i m ary focus of the present inves t iga t ion.

Co pe 's (1888) repor t of an i sola ted g lyp todo ntscute f rom Nueces County , Texas , which hen a m e d Glyptodon petaliferus, has genera l ly beencons idered the f i r s t indica t ion of g lyptodontsnor th of Mexico. Two years ear l i e r , however ,Cope (1886) had repor ted the recovery of severa lscutes and a phalanx from the Loup Fork beds ofK an sas , des i gna t i ng t h em as a new genus andspecies Caryoderma snovianum. A p p a r e n t l y o n l yFlower and Lydekker (1891) acknowledged th i sspecies; they ident i fied the genus as Canoderma,evident ly a l apsus . Hay (1908:446) credi ted S. W.Wil l i s ton for recogniz ing tha t these bones were inrea l i ty chelonian; Hay ass igned them to Testudoand s ta ted tha t they are in the col lec t ion a t theUnivers i ty of Kansas . We fol low Hay 's de termin a t i o n .


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S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Y

Soon after Cope's reports , Osborn (1903) described Glyptothenum texanum from the Blanco bedsof Texas. This is the genotypic species for al lknow n N or t h A m er i can g l yp t odon t s . The spec i mens described by Osborn were the fi rs t wel l-represented g lyptod ont rem ains recovered nor thof Mex ico. Os bor n 's descr ip t ion pred ated Brow n's(1912) descr ip t ion of Brachyostracon f rom Mexico,which is here regarde d as a jun ior syn onym ofOsborn 's genus a l though Brown's species i s va l id .

Fol lowing Brown's (1912) and Osborn 's (1903)defini t ive s tudies, an implici t controversy developed concerning the propr ie ty of the South American gener ic name Glyptodon for some of the NorthAmer ican recover ies . The cont roversy has cont inued up to the present t ime and, as demonst ra tedbelow an d in the taxo no m y sect ion, is not yetadequately resolved. Hay (1916, 1926) reportedgly pto do nts from two T ex an local i t ies , referr ingthem to Glyptodon petaliferus C ope . S i m pson(1929b) commented on the improbabi l i ty of thegenus Glyptodon i tself occurr ing in North America,declared Glyptodon petaliferus a n o m e n n u d u m , a n destabl ished for some Florida recoveries the genusand species Boreostracon flondanus. He did not designate a new name for the Texas fossi ls , however,and the i r s ta tus remained unresolved unt i l thepresent s tudy revealed the i r ident i ty as equiva lentto the Florida fossils. Simpson (1929b) also quest ioned the status of the Arizona species Glyptothenum anzonae which Gidley had described a fewyears ear l ie r . Simpson a pp are nt ly be l ieved th a tthe Arizona species represented a dist inct andu n n a m e d g e n u s .

At the t ime of Gidley's (1926) descript ion ofGlyptothenum anzonae a s econd com pl e t e ca r apacefrom the type loca l i ty had not been prepared ,and lay in s torage in the Amer ican Museum ofN a t u r a l H i s t o r y . Th i s ca r apace w as p r epa r ed a tappr o x i m a t e l y t he t im e o f pub l i ca t i on o f Gidley's(1926) report , but he evident ly never had theoppor tuni ty to examine i t , for i f he had, hecer ta in ly would have a l te red h i s ideas concerningthe Arizona species.

In teres t in Nor th Amer ican g lyptodonts soonaba t ed . O nce G i d l ey , H ay , and S i m pson had

es tabl i shed the cer ta in ty of Ple i s tocene g lyptodonts in Nor th Amer ica and the probabi l i ty ofsevera l t axa , g lyptodonts rece ived only sporadica t tent ion. Sel la rds (1940) mainta ined the unresolved cont roversy concerning the exis tence ofGlyptodon in North America, referr ing several specimens f rom Bee Co un ty , Tex as , to Glyptodon petaliferus.

Meade (1953) appears to have been par t lyinf luenced by pr ior remarks concerning the Hol -loman G r ave l P i t ( O k l ahom a) g l yp t odon t t ha tHay and Cook (1930) had repor ted some yearsearl ier . Simpson (1929b) s tated in a footnote thathe had exam i ned t he H ol l om an spec i m ens andtha t they probably represent an undescr ibed species. Meade ( 1953) , i n r epor t i ng t he H ol l om anfauna , be l ieved tha t the g lyptodont be longed ina separa te genus , and he accordingly es tabl i shedXenoglyptodon fredencensis.

The di scovery of g lyptodonts in the Gi l l i l andfaunal hor izon of the Sey mo ur Form at ion innor thern Texas was repor ted f i r s t by Mel ton(1964) and soon thereaf ter by Hibbard andDa lque st (1966) . M elto n briefly describe d thisextensive ser ies of specimens, including excel lentskul l material ; he assigned them to the genusGlyptodon and cor rec t ly recognized the i r ident i tyw i t h t h e H o l l o m a n g l y p t o d o n t . T h e c o m p r e h e n s ive s tudy of the Seym our fauna s by Hib ba rd andDalques t (1966) f i rmly es tabl i shed the contempor ane i t y of t he Seym our and H o l l om an faunas ,lending suppor t to Mel ton 's speci f ic de terminat i on . C om par i ng t he Seym our g l yp t odon t s t opub l i shed accoun ts of Sou th Am er ican represent a t ives , Mel ton found the c loses t resemblance tothe genus Glyptodon, in the classic sense, and hetherefore referred to Xenoglyptodon as a ju ni or synonym; he re ta ined Meade 's species , however , re co r d i ng t he Seym our and H o l l om an g l yp t odon t sas Glyptodon fredericensis.

A com pr ehens i ve exam i na t i on o f N o r t h A m er ican g lyptodonts in the present s tudy indica test ha t t he Seym our and H ol l om an g l yp t odon t s a r einseparable f rom Glyptothenum anzonae. At thet i m e o f M e l t on ' s ( 1964) and H i bb a r d andDalquest 's (1966) s tudies, i t was bel ieved that the


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Seym our fauna r ep r esen t s t he m i d - P l e i s t ocene ,Kansan g lac ia l age . Thus there was be l ieved tohave been representa t ive species f rom the Blanca n {Glyptothenum texanum), ea r l y I r v i ng t on i an (G .anzonae), l a t e I r v i ng t on i an [Glyptodon fredericensis),a n d R a n c h o l a b r e a n (Boreostracon floridanus). W i t hthe revis ion of the age of the Seymour fauna byH ib ba rd a nd D alqu es t (1973) , i t is c lear tha t theC ur t i s R an ch fa una ( con t a i n i ng t he ea r ly I r v i ng tonia n g ly ptod ont ) is not as grea t ly sepa ra ted int ime from the Seymour fauna as previous ly bel i eved, for Hibbard and Dalques t (1973) havepropose d tha t the Sey mo ur Gi l l i l and fauna is pre-K an san in age . T he g l yp t odo n t s supp or t t he i rco nte nt i on , for the re are no significant differencesbe t w een t he Seym our and C ur t i s R anch r ep r e sen t a t i ves . Thus Glyptodon fredericensis is here cons idered to be a jun io r syno nym of Glyptothenumanzonae.

Pe rha ps the pr inc ipa l cause of confus ion rega r d i n g the taxon om y of N o r t h A m er i can g l yp todo nts has been the genera l l ack of c rania l ma ter ia l . Only the incomple te skul l remains of theWolfe Ci ty , Texas , g lyptodont descr ibed by Hay(1916) were known wi th any measure of conf i dence prior to Melton's (1964) report of the Seymour col lec t ion, which inc ludes some excel lentsku l l m a t e r i a l . Lack i ng adequa t e r e fe r ence m ater ial for the Seymour skul ls , Melton resorted topub l i shed descr ip t ions of So uth Am er ica n g lyptodont skul l s . Mel ton 's s tudy was the f i r s t a t t emptt o p l ace t axon om y o f N o r t h A m er i can r ep r esen t a t i ves on a founda t i on com par ab l e t o t ha t e s t ab l i shed for South Amer ican g lyptodonts , for whichcrania l and carapacia l e lements have rece iveda p p r o x i m a t e l y e q u a l a t t e n t i o n .

The addi t ion of several excel lent skul ls of theA r i z o n a p o p u l a t i o n oi Glyptothenum texanum in thiss tudy has sub s tant ia l ly m odi f ied the conclus ionsr eached by p r ev i ous w or ke r s conce r ned w i t hN or t h A m er i can g l yp t odon t s and has r evea l edt he c l ose r e l a t i onsh i p am ong a l l N or t h A m er i canr ep r esen t a t i ves .

R ecen t r epor t s on N or t h A m er i can g l yp t odon t sinc lud e tha t of R ay (1965) , wh o record ed a par t ial skul l of a glyptodont recovered from coastal

South Carol ina , ident i f i ed here as Glyptothenumflondanum; and t ha t o f Lu nde l i us ( 1972), w hodiscussed the g lyptodont in the Late Ple i s toceneI ng l e s i de fauna f r om San Pa t r i c i o C oun t y , Texas .Lu nde l ius ' s s tudy is the most recent t ax on om icr ev i ew o f N or t h A m er i can g l yp t odon t s .

Systemat icsT a x o n o m y of N o r t h A m e r i c a n g l y p to d o n t s h a s

been based p r i m ar i l y on ca r apac i a l and pe l v i ccha r ac t e r s , a consequence o f t he l i m i t ed num berand charac ter of specimens avai lable . I t i s for tuna te tha t g lyptodonts were not recognized inNor th Amer ica unt i l l a te in the 19th century ,w hen t he num ber o f p r oposed spec i e s and gene r afor So uth Am er ica n g lyp todo nts reache d i ts zeni th . At tha t t ime severa l authors (e .g . , Burmeis -ter , 1874; Lydekker, 1894) sought to evaluate theex i s t i ng a r r ay o f nam es f r om a m or e "ba l anced"perspect ive . The or ig in of the confus ion lay in theins i s tence of previous wo rkers on es tabl i sh ing newspecies (and even genera) whenever a new carapace , o r a pa r t i a l ca r apace , w as found . A ppa r ent ly th i s ear ly t ende ncy of excess ive " spl i t t in g"occur r ed because no t w o i nd i v i dua l g l yp t odon tcarapaces are exact ly a l ike , nor are res tora t ionsever exact ly a l ike , wh ich un do ub ted ly affec ts adescr ip t ion despi te an author ' s awareness tha t apa r t icu lar aspect is not exact ly cor rec t . T h e p le tho r a o f nam es ev i den t l y exaspe r a t ed t hose w h osought an ov erview, as expressed by L yde kke r(1894:3) :A l arge nu m be r o f t he so -c a l le d ge ne ra an d spe c ie s havebe e n e s t ab l i she d on t he e v i de nc e of suc h f r agm e n t ary an dimperfec t sp ec im ens that i t i s f requ ent ly a lmo st or qui t ei mposs i b l e t o de t e rmi ne t o what f o rms t he y r e a l l y be l ong ,an d I have ac c o rd i ng l y m ad e no a t t e m pt t o g i ve t he c om pl e t esynonomy of a g roup whose s t udy has be e n made unne c e s sar i l y c ompl e x by i nc ompe t e n t worke r s . In add i t i on t o t hef ac t t ha t many nomi nal ge ne ra and spe c i e s have be e n f o rme dupo n t he e v i de nc e o f spe c i m e ns t ha t oug h t ne ve r t o havebe e n de sc r i be d a t a l l , o t he r s have be e n m ad e by t ak i n gport ions of the carapace f rom a di f fe rent region f rom that towhich the type of the form to which they real ly be longpe r t a i ne d . Ot he r s , aga i n , have be e n e s t ab l i she d on t he r e m a i n s o f i m m a t u r e o r y o u n g a n i m a l s ; a n d w e t h u s h a v e , i n


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6 S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Ywhat i s real ly a rather smal l group, a host of meaninglessnam es which it is almos t imp ossible to corre late .

I t was approximate ly a t the t ime of Lydekker ' ss tudy tha t the exis tence of g lyptodonts in Nor thAmer ica became es tabl i shed, and Nor th Amer i can authors wise ly were re luc tant to counter Lydekker 's (1894) and Burmeister 's (1874) admonit ions . Indeed, only three names have been proposed for carapacial remains alone, to the exclus ion of noncarapacia l charac ters . These are Glyptodon rivipacis H a y , Glyptodon petaliferus C ope , andBoreostracon flondanus Si m pson .

Glyptodon rivipacis Hay obvious ly was proposedimproperly and has not been considered as val id.Because i t was proposed for some of the glyptodont scutes from Peace Creek, Florida, withoutdes ignat ion or descr ip t ion, Simpson (1929b) cor rect ly considered Glyptodon rivipacis a nom en nud u m .

Cope's species was based on an isolated andfragmentary scute. Recognizing the fut i l i ty oftaxonomic charac ter iza t ion based on i sola tedscutes, Simpson (1929b) also declared Glyptodonpetaliferus a nomen nudum, impl ic i t ly replac ingthi s name wi th Boreostracon flondanus. (Simpsonalso bel ieved that the Texas glyptodonts , referredto G. petaliferus by Co pe , 1888, 1889, an d by H ay ,1916, 1926, actual ly belonged to a species dist inctfrom the Florida species, but he did not designatea new name. )

Boreostracon flondanus Simpson was erected for alarge ser ies of part ial carapaces and isolated scutesfrom Florida. Simpson effect ively expandedCope 's procedure of re l i ance on carapacia l feat u r e s , com pound i ng t he i m pr opr i e t y o f t axonomic des ignat ion of type specimens wi thoutnoncarapacia l remains . Because the hypodigm ofSim pso n's species is dist inct ive a nd fully re presentat ive, this name is here retained.Brown (1912) , Gidley (1926) , an d Lu nd el ius(1972) , among others , have cons idered noncarapacia l e lements in the i r t axonomic determinat ions . The unusual s i tua t ion of having pelv icelements for almost al l of the various North American popula t ions has prompted the cons idera t ionof pe lv ic charac ters as pr inc ipa l t axonomic deter

minants . Skul l s and dent i t ions have been la rgelyunknow n, even am ong Sou t h A m er i can t axa ,thus necess i ta t ing subordina t ion of these t radi t ional ly impor tant ske le ta l par t s . We re ly heavi lyon character is t ics of the skul ls and dent i t ions aspr inc ipa l t axonomic fea tures , thus p lac ing Nor thAmer ican g lyptodont t axonomy on a foot ing s imi la r t o t ha t o f m os t o t he r m am m al i a n t axa . T hedetai led study of the total osteology of NorthAmer ican representa t ives reveal s the i r c lose ,ra ther than d i s tant , re la t ionships . Skul l s and dent i t ions rece ive impor tant cons idera t ion in the taxonomy proposed here . This new informat ion i saugm ent ed s t r ong l y by t he r eexam i na t i on o f ca r apacia l and pelv ic fea tures , reveal ing tha t manyof the differences previously considered to befun dam enta l indica t ion s of d i s tant re la t ionshipsare ei the r m isin terp reta t ion s or unjust i fied inflat ion of the re la t ive impor tance of noted d i s t inct ions.

To the ca tegory of mis in terpre ta t ions be longsthe taxonomic f ramework based on carapacia lfea tures . Improper res tora t ion of the type speci mens of Glyptothenum anzonae, as an example , hasbeen i m p or t an t . Subsequ en t m i s i n t e r p r e t a t i onsof Gidley s (1926) descript ion, owing to i ts incomple teness and a mis leading photograph, soon fo l lowed, and became incorpora ted as fac t .A no t he r exam pl e o f m i s i n t e r p r e t a t i on o f ca r a pacial features resides in the series of specimenstha t Simp son (1929b) des ignated as para type s forBoreostracon flondanus. As postulated in the osteo-logical descript ion of the carapace, most of thespecimens Simpson chose apparent ly representfemale individuals , whi le carapacia l remains ofm a l es w er e r ega r ded a s "abnor m a l l y l a r ge . " H adhis description i nc l uded t he num er ous l a r gescutes, there l ikely would have been early recogni t ion of the congeneric relat ionship of his specieswi th o ther Nor th Amer ican species . Ins tead , because Simpson's ser ies heavi ly favored the smallerscutes (because they were by chance in mostextens ive ar t i cula t ion) those of the males havebeen ignored, and Simpson 's c la im of gener icd i s ti nc t ion has been pe r p e t ua t ed .

To the second ca tegory , tha t of unjus t i f i ed


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inf la t ion of the impor tance of noted d i s t inc t ions ,be longs the usage of pe lv ic charac ters in separat ion of h igher ca tegor ies . For example , Brown(1912) , in part because of the nature of the pelvis ,not only es tabl i shed the genus Brachyostracon, b u the also placed this genus in a family separatefrom the only o ther Nor th Amer ican species(Glyptothenum texanum) known a t the t ime. Fami l ia l and subfami l ia l separa t ion on the bas i s ofpelv ic cha rac te rs is un w ar ran ted an d even gener icsepa ra t ion on th e bas i s of pe lv ic cha rac te rs is heredenied , in the be l ie f tha t carapacia l and denta ls imi lar i t i es fa r outweigh the impor tance of pe lv icdist inct ions. This assert ion is founded on the reex-am i na t i on o f t he ca r apaces , den t i t ions , and pe lveso f N or t h A m er i can r ep r esen t a t i ves ; t he supp or t ing arguments a re drawn from the gross os teologyof these and other skele ta l regions . The ques t ionof re la t ive impor tance of pe lv ic charac ters deserves fur ther comment , however , s ince the pe lv i shas rece ived cons iderable a t tent ion.

I t i s imposs ib le to de termine whether there i ssexual d im orp hism in g lyp todo nt pe lves on thebas i s of the smal l Nor th Amer ican sample . Nor i si t possible with certainty to evaluate the differences in cons t ruc t ion and var ia t ions in the number of ver tebrae par t i c ipa t ing in the severa l component regions of the pelvis . Because the pelvesare so wel l represe nted , a nd becau se ear l ie r au thors have used character is t ics of the pelvis int axono m i c de t e r m i na t i on s , it is app r op r i a t e t oexamine the pe lves of two extant edenta tes . Thefol lowing digression is inc lud ed to poi nt up theweakness of dependence on pelv ic charac ters intaxonomy of l iv ing edenta tes , and by analogy, ofthe ext inc t g lypto don ts .

In a small sample of s ix skeletal specimens oft h e n i n e - b a n d e d a r m a d i l l o , Dasypus novem cinctus,of know n sex ( U SN M D i v is ion of M am m al s5332Id, 244905(5, 249906c?, 256760$, 25676Id,493 98?) , th ere is s ignificant va riat io n in the ilio-sacra l and i schiosacra l unions . In two males(256761 and 53321) there are only two i l iosacralver tebrae . In the o ther two males and in bothfemales there are three i l iosacra l ver tebrae . Apparent ly as par t i a l compensat ion in the two spec

imens wi th only two i l iosacra l s , the pos ter ior lumbar ver tebra par t i c ipa tes more s t rongly in thepe l v i c s t r uc t u r e t han does t he co r r e spond i ng ve r tebra of the specimens wi th three i l iosacra l s . Especial ly in 5 3 3 2 1 , this vertebra possesses great lyexpanded t ransverse processes tha t contac t thei l ium bro adly , a l lowin g pa r t ic ip a t io n of th i s ver t eb r a as an an t e r i o r "pseu do- sac r a l " v e r t eb r a .

T he re is s imi lar var ia t ion in the co ns t ru c t ionof the i schiosacra l union in the same sample . Inal l s ix specimens there are four ischiosacral vertebrae tha t par t i c ipa te in th i s union by fus ion ofthe i r expanded t ransverse processes wi th the i s -c h i u m . For three of the males (53321 , 244905 ,244906) the t ransverse processes of the terminalsacral vertebra are sol idly fused both with thei schium and wi th the t ransverse process of theadjacent penul t imate sacra l ver tebra . In one specime n (244905) the ce nt ru m of the last sacralver teb ra i s fused to tha t of the pe nu l t im ate vertebr a ; the ce nt ru m is unfused in the o th er twomales despi te the ankylosis of their t ransverseprocesses.

In marked cont ras t , the t ransverse processes ofthe o ther male and the two females (256761 ,25676 0, an d 493 98, respect ively) are fused o nlywi th the i schia and not wi th the t ransverseprocesses of the penul t imate sacra l ver tebra . Inall thre e spe cim ens the last ce nt ru m is not fusedt o t he one an t e r i o r . C onsequen t l y , t he t e r m i na lsacra l ver tebra , par t i c ipa t ing in the i schiosacra lunion, more c lose ly resembles the anter ior caudalver tebra (pos ter ior "pseudo-sacra l") than the adjo in ing sacra l ver tebrae . Indeed, the fus ion of thetransverse processes with the ischia is incompletein 256760 and 2 5 6 7 6 1 , in which th i s contac tremains car t i l aginous . In the foss i l s t a te , wi thoutcomple te ver tebra l columns for reference , theseterminal sacra l ver tebrae could eas i ly be mis takenfo r t he an t e r i o r cauda l ve r t eb r a , and t he r e w ou l dtherefore exist an ar t i ficial dispari ty in the ischiosacra l count for these specimens .

In al l s ix specimens there are two free vertebraein the sacra l a rch , a l though the par t i c ipa t ion oft he t r ansve r se p r oces ses o f t he an t epenu l t i m a t ever te bra i s var ia ble , f rom full pa r t i c ip a t io n, to an


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8 S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Yes t ima ted one -qu ar ter pa r t i c ipa t io n ( i. e. , the obtura tor foramen is more pos ter ior ly s i tua ted ) . Remaining character is t ics of the pelvis of D. novem-cinctus are re la t ive ly cons tant . The pubes are s toutin both sexes and they uni te at the midl ine in astrongly ankylos ed con tact . Th er e is l i t t le evidentvar ia t ion in the compound curvature of the sacrum. In al l s ix specimens the fi rs t two caudalve r t eb r ae r e sem bl e t he "pseudosac r a l " cons t r uc t ion of g lyptodonts .

Thus in the n ine-banded armadi l lo , there i sconsiderable variat ion in the pelvis . None of thevariat ion is at t r ibutable ei ther to age or sex;ins tead , i t appears to be s imple individual var ia t ion, and i t evident ly bears no taxonomic signifi cance for this species.

Similar ly, in two male specimens of the gianta r m ad i l l o Pnodonles gtganleus (USNM Divis ion ofM am m als 261024, 299630) , there is a m arke ddi fference in the con t r ibut io n of the te rmin alsacral vertebra. In specimen 299630 the t ransverse processes are fused with the adjoining t ransverse processes of the penul t imate ver tebra andwith the ischia. In the other specimen the t ransverse processes are free, remaining unfused withei ther the ischia or the adjoining t ransverseprocesses. This variat ion cannot be an age-relatedphenomenon, for the individual wi th the f reepos ter ior sacra l ver tebra appears to be o lder thanthe other . The pelves of these two individuals areotherwise ident ica l .

Thus by analogy with armadil los, i t i s l ikelythat th e am ou nt of intraspecific varia t ion in theglyp tod on t pelvis is grea ter than B rown (1912)had supposed. Accordingly, the differences in thepelves of the Nor th Amer ican representa t ives a renot necessari ly indic at ive of supraspecific dist inct ion . V ar ia t io n in ver tebra l par t i c ipa t ion in thesacral arch should not be accorded principal taxonomic significance, nor should the size of thepubic cross bar be considered as a pr imary taxonomic cha rac ter . V ar ia t ions in the pelv is a re hereproposed as no more than species dist inct ions, forther e is no just i ficat io n for basing gen eric diag noses on the pe lv i s . The amended diagnoses reflect these content ions.

To this point in the discussion, the congenericstatus of Boreostracon, Brachyostracon, a n d Glyptothenum has been m en t i oned . Glyptothenum O s b o r n ,1903, has pr ior i ty , an d th i s is the gener ic na m ethat i s here appl ied to al l know n N or th Am er icang l yp t odon t s .

Xenoglyptodon M e a d e , 1953, was reduced to synony my by M el ton (1964) , wh o cor rec t ly cons ide r ed t he H ol l om an ( O k l ahom a) g l yp t odon t s a sident ica l to the Seymour (Texas) representa t ivesbut refer red the Seymour and Hol loman speci m ens t o t he Sou t h A m er i can genus Glyptodon.

The presence of the genus Glyptodon in Nor thAmerica was fi rs t proposed by Cope (1888) . Hay(1916, 1926) and Sel lards (1940) fol lowed Cope'sassert ion, while Brown (1912) , Gidley (1926) ,Simpso n (1929b) , an d Holm es an d Simpso n(1931) , am on g ear ly No r th Am er ican auth ors ,denied the existence of this genus in the NorthA m er i can fauna . S t uden t s of Sou t h A m er i cang l yp t odon t s , appa r en t l y i nva r i ab l y , have den i edthe existence of Glyptodon in Nor th Amer ica , recogniz ing only Glyptothenum a n d Boreostracon. Mel ton's (1964) resurrect ion of the generic nameGlyptodon for the Seymour g lyptodonts i s thereforeques t ionable f rom a h i s tor ic s tandpoint . Moreim po r tan t , however , is the fac t tha t th e N or thAmer ican g lyptodonts a re a l l c lose ly re la ted , andapp are nt ly represent evolut ion f rom a s ingle earlyPleistocene immigrant . At least for three species,Glyptothenum texanum, G. anzonae, a n d G. floridanum.an ances t ra l -descendant re la t ionship can be proposed wi th subs tant ia l bas i s . The other two species, G. cylindricum a n d G. mexicanum, of which thelat ter is nominal ly retained, are not as easi lyplaced in the sequence , pr imar i ly because theyare poor ly known. They appear to represent aspecies (or , nominal ly, two species) contemporaneous wi th the more nor thern Late Ple i s tocene G.floridanum, i f not ac tua l ly per ta in ing to the samespec ie s. Th us t he N or t h A m er i can g l yp t odon t sare not only closely related, but they also appearto have an i sola ted h i s tory , apparent ly qui te apar tf rom South Amer ican re la t ives . Moreover , theear ly or ig in of the Nor th Amer ican l ineage (Ear lyPleistocene-Blancan L a n d M a m m a l A g e ) c o i n -


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cides t empora l ly wi th only one S o u t h A m e r i c a nspecies of Glyptodon, G. laevis Burmeister; the rem ai n i ng Sou t h A m er i can spec i e s are l isted byCaste l lanos (1954) as M i d d l e or Late Ple i s toceneand , t he r e fo r e , canno t be cons i de r ed as ances t r a lor closely related on t e m p o r a l g r o u n d s . The rel a t i onsh i p of the ances t r a l N or t h A m er i can spe cies, Glyptothenum texanum, with the a p p a r e n t l yc o n t e m p o r a n e o u s Glyptodon laevis ( c o n t e m p o r a neous in the broad sense , and accep t i ng C as t e l lanos ' (1954) affi rmation of the val id i ty of thisspecies) of Sout h A m er i ca s eem s to be no closert han t ha t be t w een G. texanum and o t he r Sou t hAmer ican species of th i s genus . Nor does therea p p e a r to be any closer re la t ionship be tween theNo rth Am er ican species , col lec t ive ly or indiv idual ly, with the species oi Glyptodon t han w i t h o t he rSouth Amer ican species in the subfam i l y G l y p -t o d o n t i n a e .

The p r eced i ng com m ent s a s sum e va l i d i t y ofthe genus Glyptodon, a m a t t e r t h a t in itself, andqu i t e apa r t f r om t axonom i c p r ob l em s in N o r t hAmer ica , deserves specia l a t t ent ion. The s t a t us oft he gene r i c nam e Glyptodon has been reviewed byHoffstet ter (1955) , who discussed the i n a p p r o p r i a t e c i r cum s t ances su r r ound i ng the origin oft h i s nam e . The gene r i c nam e Glyptodon has beenapplied, classical ly, to a g r o u p for w h i c h theor ig ina l descr ip t ion (Owen, 1838) does not a p p l y ,at least in pa r t . H of f s t e t t e r r ecom m ended des i g na t i on of a l ec t o t ype co r r e spond i ng to the r ea rfoot tha t Owen descr ibed and t ha t pe r t a i ns inac t ua l i t y to the g e n u s in the classic sense ( that is,as has been accep t ed by s u b s e q u e n t c o m m o nusage ) . Whe t he r the recourse Hoffs te t te r has sugges ted , which seems a l together reasonable , wi l lga i n fu t u r e accep t ance is u n c e r t a i n . For the present , however , it w o u l d be p r e m a t u r e to assignN o r t h A m e r i c a n g l y p t o d o n t s on the basis of aSout h A m er i can genus of unce r t a i n s t a t us . C e r ta in ly the g r o u p of g l y p t o d o n t s to w h i c h then a m e Glyptodon has been app l i ed is a uni f ied andcha r ac t e r i s t i c g r oup , and it has b e e n the subjec to f s eve ra l t axon om i c r eeva l ua t i ons am on g w h i cht h a t of Caste l lanos (1954) is p e r t i n e n t to thet a x o n o m y of N or t h A m er i can r ep r esen t a t i ves .

F i na l l y , app l i ca t i on of the gene r i c nam e Glyptodon to North American fossi ls would suggest acloser re la t ionship than the ev i dence at h a n dw a r r a n t s . The N or t h A m er i can g l yp t odon t s , inal l respect s members of the subfam i l y G l yp t odon-t i nae , are dis t inc t f rom thei r South Amer icanre la t ives , and the exis t ing lower level t axonomysho uld reflect this s i tua t ion by r e t en t i on of asepa r a t e gene r i c nam e . The exis tence of so-calledBoreostracon in S o u t h A m e r i c a is q u i t e a n o t h e rm a t t e r , and t he r e is no reason to deny the possibi l i ty of secondary invas ion of the N or t h A m er i can r ep r esen t a t i ves back i n t o Sou t h A m er i ca .

A l t h o u g h the t axonom y p r oposed he r e is asubs t an t i a l a l t e r a t i on of the previous ly acceptedclassification of N or t h A m er i can g l yp t odon t s , thechanges are s u p p o r t e d by a grea t expans ion int h e n u m b e r of specimens , inc luding skul l s andden t i t i ons . The upper level classification followsSimpson (1945) and Caste l lanos (1954) .O r d e r EDENTATA C u v i e r , 1798

S u b o r d e r XENARTHRA C o p e , 1889I n f r a o r d e r CINCULATA Il l iger, 1811

S u p e r f a m i l y GLYPTODONTOIDEA S i m p s o n , 1931F a m i l y GLYPTODONTIDAE Burme i s t e r , 1879

S u b f a m i l y GLYPTODONTINAE T r o u e s s a r t , 1898G e n u s Glyptothenum O s b o r n , 1903

Glyptothenum texanum O s b o r n , 1903G. arizonae Gi d l e y , 1926G. floridanum ( S i m p s o n , 1929)G. cylmdricum (Brown , 1912)G. mexicanum ( C u a t a p a r o and R a m i r e z ,

1875)A s acknow l edged by Simpson (1945) andHoffs te t te r (1958), am on g others , the familyn a m e G l y p t o d o n t i d a e B u r m e i s t e r , 1879, hasga i ned the a d v a n t a g e of usage ove r H op l ophor i -d a e H u x l e y , 1864. Excep t for the p r o b l e m a t i c a lEa r l y Te r t i a r y genus Palaeopeltis A m e g h i n o , 1895,a l l g l yp t odon t s be l ong in the fami ly Glyptodont i dae . The t axonom i c pos i t i on of Palaeopeltis hasnot be en resolved; som e (e.g. , Ca stel la nos , 1954)assign this genus to a separa te fami ly , whi le o thers(e.g. , Simpson, 1945) conservat ive ly declare itss ta tus to be incertae sedis .

Simpson (1945) recognized four subfamil ies ofGlyptodont idae , whereas Hoffs te t te r (1958) rec-


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10 S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Yognized five by choosing to spl i t off two generafrom Simpson 's recognized subfami ly Propalaeo-hop loph or ina e Cas te l lanos , 1932, to be inc lud edin a separa te subfami ly . The remaining threesubfamil ies seem to be well establ ished: Hoplo-phorinae Weber, 1928 ( this is Simpson's , 1945,preference ; Hoffstet ter , 1958, retain s the oldernam e Sclerocalyp t inae Troues sar t , 1898, for thesam e a s sem bl age ) ; D oed i cu r i nae Tr oues sa r t ,1898; and G l yp t odon t i nae Tr oues sa r t , 1898 .

Brown (1912) bel ieved that his genus Brachyostracon belonged in a family separate from Glyptothenum. Simpson (1945) formalized this bel ief byp l ac i ng Brachyostracon in the subfami ly Hoplo-phor i nae , and t he r em a i n i ng N or t h A m er i cantaxa in the subfami ly G lyp todo nt ina e . Hoffs te t te r(1958) recognized the closer relat ionship betweenBrachyostracon and the o ther Nor th Amer ican genera, placing i t also in the subfamily Glyptodont inae .

Castel lanos (1954) divided the subfamily Glyptodont inae in to three t r ibes , according to whichthe Nor th Amer ican genera Glyptothenum a n d Boreostracon were separa ted . He apparent ly a l so bel ieved that Brachyostracon belonged in a separa tesubfamily, for he did not include i t in the Glyptodont inae (Cas te l lanos , 1953, 1954) . Accordingto the de term inat io ns of the present inves t iga t ion,a l l Nor th Amer ican g lyptodonts be long in thegenus Glyptothenum Osb orn, 1903, and the m at te rof t r iba l des ignat ion deserves re in terp re ta t ion .

Subfami ly G L Y P T O D O N T I N A EHoffstet ter (1958) has provided the most com

prehensive review of the characters of thissubfamily. The fol lowing features are some of themore per t inent ones tha t d i s t inguish the Glyptodo nt in ae f rom the o the r subfami l ies : (1) carapa cedivided into long thoracic region and short lum-bosacral region; (2) scutes thick, with s imple orna m en tat io n; (3) m arg ina l scutes most ly different ia ted in to a h ighly tuberculatcd cons t r uc t i on ;(4) caudal a rmor composed of movable r ings ,each formed by two or three rows of plates , ofwhich those in the poster ior row are sometimes

con i ca l o r t ube r cu l a t ed ; t e r m i na l a r m or anky-losed into a short tu be (H offstet ter , 1958, s tat edthat the caudal armor consists of only sevenindividual r ings ; evidence presented here in indi ca tes tha t the nu m be r of cau dal r ings is var iab le) ;(5) skul l l a rge , t a l l , and abrupt ly t runcated because of shor tening of the nasa l s , premaxi l lae ,an d anter ior end of m an dib le ; (6) nar ia l ap er tu retrapezoidal and tal l ; (7) upper profi le of the skul ls t ra ight and inc l ined forward; (8) zygo ma t ic a rchra ther weak pos ter ior ly ; descending processesmassive; (9) postorbi tal bar incomplete; (10) teethal l t r i lobed, but anter ior ones smaller ; (11) osteo-dent ine cores form numerous secondary ramif i ca t ions , a condi t ion not known in the o thersubfami l ies ; (12) humerus lacks the entepicon-dylar bridge, which is present in the othersubfamilies; (13) manus with no more than fourdigi ts ; pes with five complete digi ts .

Al l of the Nor th Amer ican g lyptodonts examined in the present s tudy conform to Hoffstet ter 's(1958) character is t ics for this subfamily. Some ofthe features listed below in the diagnosis forGlyptothenum might a l so per ta in to the ent i resubfami ly .

G enus Glyptotherium O sborn"Glyptodon' o f C u a t a p a r o a n d R a m i r e z , 1 8 7 5 : 3 6 2 . C o p e ,

1888:346 .Hay, 1916:107 .Sel l a rds , 1940:1637 .Mel ton, 1964:131.

Glyplolhtnum O s b o r n , 1 9 0 3 : 4 9 2 G i d l e y , 1 9 2 6 : 9 6 A k e r-s ten, 1970:13.

Brachyostracon B r o w n , 1912:169.Boreostracon S i m p s o n , 1929b:581 .Lunde l ius , 1972:36 .Xenoglyptodon M e a d e , 1953:455.

A G E . L a t e Pl iocene to Late Ple i s tocene; LateB l a n c a n t h r o u g h R a n c h o l a b r e a n L a n d M a m m a lAges.

DIAGNOSIS.Size medium to la rge; skul l shor t ,t runcated, dorsal profi le flat , anter iorly incl ined;nasa l aper ture t rapezoida l ; pos torbi ta l bar incomple te ; d ig i t I , manus , absent , d ig i t s II, III, IVlarge , d ig i t V redu ced; d ig i t s I an d V , pes , smal l ,reduced, d ig i t s I I , III, I V l a r ge ; hum er us l ack i ngentepicondylar fo r am en ; cauda l ve r t eb r ae un-


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NUMBER 40 11

fused, each protected by individual, movablerings, except the "sacrocaudals" and the last twoor three, which may be fused into a short tube;scutes of distal row of each caudal ring weakly tostrongly conical; first caudal ring incomplete;chevron distal articulation with caudal ring ofnext posterior vertebra; carapace short, arched,usually with posterior recurved outline; cephalicboss may be present on carapace; carapacialscutes firmly articulated, immovable except inanterolateral region; individual scutes polygonal,with rosette sculpturing; central figure largerthan, or equal to, size of peripherals; one rowperipherals, with occasional intercalations of incomplete second row; central figures weakly convex, flat, or weakly concave; peripheral figuresfiat; scutes of caudal border weakly to stronglyconical; nuchal scutes usually unbossed; scutes ofanterolateral region quadrilateral, movable; lateral border scutes variously conical, pendant.

Glyptothenum texanum OsbornGlyptothenum texanum O s b o r n , 1903:492, pi. 4 3 . A k e r s t e n ,

1972:13, f igs. 8d,e, 9a,b.T Y P E SPECIMEN.AMNH 10704 carapace,

caudal vertebrae, caudal armor, pelvis, sevenchevrons.T Y P E - L O C A L I T Y . L l a n o Estacado, Texas; ex

act locality uncertain; probably "Blanco Locality," Crosby County, Texas, of Johnston andSavage (1955).

R E F E R R E D SPECIMENS.The following specimens are referred to G. texanum Osborn.

Type-Locality: AMNH 10705, several scutes(unseen); AMNH 20092, from Crawfish Draw,Blanco Canyon, probably scutes (unseen).Cita Canyon Locality, Randall County, Texas,Bed no. 4: JW T 1723, tibiofibula; JWT 1712,calcaneum; J WT 2330, fragmentary right andleft mandibles, isolated teeth an d tooth fragments; J WT 1837, isolated rear upper tooth;JWT 1715, nearly complet e mand ible with broken Ni-Ns; JWT 649, 13 articulated scutes, 119isolated scutes; J WT 2319, 120 isolated scutes;

JWT 2387, 10 articulated scutes; J WT 1907, 9articulated scutes; J WT 1706, 10 articulatedscutes, 10 isolated scutes; JWT 2356, 2408, 2477,2 5 0 1 , 2578, 22 isolated scutes; JWT 649, isolatedrear ungual phalanx.

Red Light Local Fauna, Love Formation, Hud-speth County, Texas: TMM 40961-1 , partial carapace an d numerous isolated scutes; T MM40664-245, distal end right humerus; T MM40664-109, ungual phalanx.

Hudspeth Local Fauna, Camp Rice Formation, Hudspeth County, Texas: T MM 40254-1 ,40254-2, 40254-3, 40255-2, isolated scutes.

Tusker Local Fauna, Graham County, Arizona: F:AM 59581 , carapace; F:AM 59583, partial skull; F:AM 59584, radius; F:AM 59589, twoscutes; F:AM 59599, carapace; F:AM 95737,nearly complete skeleton and carapace; F:AM59586, astragalus; F:AM 59584, phalanx; F:AM59585 , radius.

A G E . B l a n c a n Land Mammal Age, Late Pliocene-Early Pleistocene.

DIAGNOSIS.Skull small; glenoid fossa smooth;paroccipital processes small; paroccipital canallacking; basioccipital-basisphenoid contact invertical plane of posterior nares; basioccipital-basisphenoid union contiguous, in same plane;inferior border of foramen magnum entire, basi-occipital not deeply clefted; squamous occipitalsmooth an d inclination shallow; occipital con-dyles conical; hypoglossal canal lacking; ventralextremity petromastoid rounded; medial parietalregion not elevated; mental foramen in plane ofNT midlobe; inferior margin of horizontal ramusof mandible flattened; N~ ovoid; N~ trilobate;N--N8 anterior borders flattened; Ni elongate,irregularly ovoid, situated on symphyseal curvature; Ng trilobate, submolariform; Ng submolari-form, obliquity of posterior lobe intermediate; N5anterior lobe relatively undeveloped, no anteroin-ternal sulcus; Ng -N7 lobes slightly oblique; Nganteromedial an d anterolateral faces convex,apex blunt; presacral vertebrae unknown; acro-mion process of scapula symmetrical; propodialsand epipodials small and lacking greatly exaggerated features; humerus lacking supratrochlear


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S M I T H S O N I A N C O N T R I B U T I O N S TO P A L E O B I O L O G Y

foramen; ar t icular facets of m a n u s and pes smal l ,curved; five or six ver t eb r ae in l um bar t ube ; t h r eei l iosacral vertebrae; four free vertebrae in sacrala r ch ; one or two i schiosacra l ver tebrae ; pubiccrossbar small ; ischiac crests poster iorly convergen t ; com pound cu r ve of sacral arch not pr o nounced; t ransverse processes of t e rminal sacra lver tebra d i rec ted obl iquely rearward; anter iorsurface of i l ium s t rongly concavoconvex; carapace smal l , symmetr ica l anteropos ter ior ly , nothighly arched; no cephal ic boss on c a r a p a c e ;border scutes not great ly enlarged; scutes small ,central figures convex, larger than peripherals ,frequent deep hair fol l icles; poster ior border ofcarapace recurved weakly or not at all; cen t r a lfigures of scutes usual ly convex , frequent ly withdeep media l depress ion; caudal and cephal ic aper tures t aper l a tera l ly downward, not vert ical ;scutes of carapace d i sposed in t ransverse andobl ique rows; pos ter ior border scutes var iablefrom flat to weakly conical ; lateral border scutesonly s l ight ly enlarged, occas ional ly "pendant" ;nuchal scutes smooth , unbossed; caudal a rmorconsist ing of 11 separa te r ings of scutes, one r ingper ver tebra , inc luding an i ncom pl e t e an t e r i o r"accessory r ing" and a t e rminal tube formed byei ther the single terminal r ing or by fusion of thelast two rings; scutes of cauda l a r m or unbossed ,present ing uni formly sca l loped d i s ta l out l ine , except dorsal pair of scutes in r ings 4 - 1 1 , which areconica l and raised.

Glyptotherium anzonae GidleyGlyptothenum anzonae G i d l e y , 1926:96, fig. 4, pis . 40-44."Glyptothenum" anzonae G i d l e y . S i m p s o n , 1929b:582 .Glyptodon petaliferus C o p e . H a y an d Cook, 1930:10.Xenoglyptodon fredericensis M e a d e , 1953:455, pi . 1.Glyptodon fredericensis ( M e a d e ) . M e l t o n , 1964:131, figs. 2-3,pis. 1-3.

T Y P E S P E C I M E N S . U S N M 10536 (holotype),ma nd ible wi th tee th , com ple te r ight f ront l im b,ver tebra l f ragments inc luding broken dorsa l tube ,carapace por t ions , i so la ted scutes f rom carapaceand ta il r ings , com ple te r ight h ind l imb , incomplete left hind l imb; USNM 10537 and 10336

( pa r a t ypes ) , cauda l ve r t eb r ae an d c a u d a l a r m o r ,por t ions of carapace , foot bones , broken tee th .

TYPE-LOCALITY."About three miles east oft he C ur t i s R anch , in Sec. 25, T. 18 S., R. 21 E.,Cochise County , Ar izona" (Gidley , 1926) .

R E F E R R E D SPECIMENS.The fol lowing specim ens are referred to G. anzonae G i d l ey .Type - Loca l i t y : A M N H 21808 , com pl e t e ca ra pace and cauda l a r m or , cauda l ve r t eb r ae w i t hassocia ted chevrons , pe lv i s, femur ; A M N H 21809,isolated scutes (unseen) .

H o l l om an G r ave l Pit near Freder ick , TillmanC o u n t y , O k l a h o m a : TMM 934- 37 , f r agm ent a r ym and i b l e w i t h two broken tee th , two isolatedscutes; an u n n u m b e r e d c a r a p a c e in the Stoval lMuseum , U ni ve r s i t y of O k l a h o m a .

Seym our For m a t i on , G i l l i l and Loca l Fauna ,K n o x C o u n t y , T e x a s : MWU 1209, 1632, 1633,1667, 1668, 1798, 1799, 1861, 1862, 1980, 2307,2309-2315, 2317-2322, 2324, 2456, 2558, 2671,2672, 2674-2676, 2678, 7997, 7998, numerousscutes, most ly isolated; MWU 1668, 2324, caudalve r t eb r ae , MWU 1634, sacra l ver tebra f ragme nt ;M W U 1 6 6 8 , rib f r agm ent , p r ox i m a l end; U M M P33520, pha l anx ; U M M P 33524 , ti b i o fi bu l a;U M M P 4 6 4 74 , i so la te d to o t h ; U M M P 4 6 8 9 2 ,44704-44706, 44708, 44709, 22475, 46230,46240- 46257 . 46259- 46264 , 46267- 46311 ,46313- 46237 , 46341 , 46343 , 46346 , 46347 , 463 54 ,46363 , 46372, 46379, 46643, par t i a l carapaces ,caud al r ings , i so la ted scutes ; U M M P 4470 7, caudal ver tebra ; U M M P 34826, skul l, cau dal ver tebrae , chevron bones , carapace scutes , caudalr ings, a t l as , cervica l tube; U M M P 38761 , skul l ,mandible , comple te rear foot , both radi i , complete left front foot, incomplete right front foot;U M M P 46231 , complete left r ea r l i m b ; U M M P46232, broken t ib iof ibula , two isolated scutes, rib;U M M P 4 6 2 3 3 , d is ta l end of f e m u r ; U M M P46234 , f r agm ent a r y m and i b l e an d m e t a t a r s a l II;U M M P 46235 , t i b io f i bu l a d is t a l ex t r em i t y ;U M M P 4 6 2 3 6, p a t e ll a ; U M M P 4 6 2 3 7 , b r o k enm a n d i b l e s an d seven i solated scutes ; U M M P46238 , c a u d a l v e r te b r a e ; U M M P 4 6 2 3 9 , t e r m i n a lcauda l ve r t eb r a ; U M M P 46258 , m a nd i b l e f rag m e n t s , rib and severa l i so la ted scutes ; U M M P


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NUMBER 40 1346329, metatarsal III; UMMP 46330, metatarsalIII ; UMMP 4 6 3 3 1 , navicular; UMMP 46332,navicular; UMMP 46333, phalanx I, digit I,manus; UMMP 46334 metatarsal II with sesa-moid bone; UMMP 46335, teeth fragments;UMMP 46376, distal end of femur; UMMP46378, caudal vertebra; UMMP 46644, fragmentary caudal vertebra.

Specimens unseen: Glyptothenum sp. as listed inLindsay and Tessman (1974) in the Curtis Ranchfauna and equivalent faunules in CochiseCounty, Arizona.

A G E . I r v i n g t o n i a n Land Mammal Age.DIAGNOSIS.Size large, skull very large; gle-

noid fossa with distinct foramen; paroccipitalprocesses large, with deep paroccipital canal;basioccipital-basisphenoid contact posterior toposterior nares; basioccipital-basisphenoid unionobtuse, not contiguous in same plane; foramenmagnum inferior border entire; basioccipital Y-shaped; squamous occipital smooth and inclination shallow; occipital condyles conical; hypo-glossal canal lacking; ventral extremity petro-mastoid flattened; medial parietal region not elevated; mental foramen anterior to Ny; mandib-ular symphysis horizontal and flat; inferior margin of horizontal ramus of mandible rounded ;posterior margin ascending ramus of mandiblenot steeply inclined, parallel to anterior margin;N 1 ovoid; N 2 probably trilobate; N&-N8 anteriorborders flattened; Ni molariform, nearly trilobate, situated behind symphyseal curvature; Ngtrilobate, molariform; Ng molariform, posteriorlobe convex, markedly oblique, anterior lobesquared; Nj fully trilobate, transverse axes oflobes oblique, posterior face concave, no anteroin-ternal sulcus; N5-N7 lobes oblique; Ng antero-medial and anterolateral faces concave, anteriorapex pointed, anterior lobe widest, middle andposterior lobes progressively narrower, posteriorface concave, oblique; atlas free; alar processesperpendicular, struts at anterior opening of inter-vertebral foramina, posterior openings interver-tebral foramina widely separated; cervical tubeformed by vertebrae nos. 2-7; axis articular facetoriented downward; first thoracic vertebra free,

with fused rib; dorsal tube formed by 10 thoracicvertebrae; acromion process of scapula asymmetrical; propodials and epipodials large and massivewith exaggerated features; humerus with supra-trochlear foramen; articular facets, manus andpes, large and curved; three iliosacral vertebrae,one or two ischiosacral vertebrae; pubic crossbarsmall; ischiac crests slightly convergent posteriorly; moderate sacral arch compound curve;transverse processes terminal sacral vertebra directed obliquely rearward; anterior surface iliumstrongly concavoconvex; carapace large, highlyarched, divided into distinct preiliac and postiliacregions; carapace with cephalic boss; scutes large,central figures of scutes slightly greater than halfthe scute diameter, always slightly larger thanperipherals, flat to weakly convex; border of anterior aperture of carapace tapers laterally downward and rearward, posterior aperture vertical;lateral border scutes large, conical; lateral scutesof first interior row with rounded central boss;caudal armor consisting of 11 or 12 rings, including an incomplete anterior "accessory ring" anda terminal tube formed by either the terminalring or by fusion of the last two rings; dorsal pairof scutes of each ring very conical, other scutes ofdistal rows also conical and bossed; scutes ofanterior rings unbossed.

REMARKS.Large , isolated scutes from severallate Blancan to early Irvingtonian sites in Floridamost closely resemble the scutes of G. anzonaefrom Texas and Arizona. We identify these scutesas Glyptothenum sp., cf. G. anzonae Gidley. Thesespecimens and their localities are: Santa Fe River,Gilchrist County, (UF localities SF 1, 4A, 8A),UF/ FS M 10439, 10743, 10428, 10438, 19198,15122, isolated scutes, a broken tooth from a babyindividual, and two caudal ring scutes; Inglis 1A,Citrus Cou nty, UF/FS M 20568, one scute; Reynolds Point, Charlotte Harbor, Charlotte County,UF/ FS M 2774, three scutes; UF/ FS M 10322,one scute . The age of the Inglis 1A fauna is earlyIrvingtonian Land Mammal Age (Webb, 1974).The Charlotte Harbor and Santa Fe faunas pertain to the late Blancan Land Mammal age(Webb, 1974; MacFadden and Waldrop, 1980).


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14 S M I T H S O N I A N C O N T R I B U T I O N S TO P A L E O B I O L O G YGlyptothenum floridanum ( S i m pson) , new

com bi nat i onGlyptodon petaliferus C o p e , 1888:346 [nomen n u d u m ] ; 1889:

662, fig. 2 L e i d y , 1889b:25, p i . 4: fig. 9; pi. 5: figs. 11 -12; pi. 6: figs. 1-3.Hay, 1916:107, pis. 3-5; 1923:381;1924:2 , 4; 1926:2 , pi. 1: fig. 1; pi. 2: fig. 3; 1927:286.Sellards , 1940:1637, pi . 2: fig. 3.

Glyptodon flondanus Leidy , 1889a [nomen v a n u m ] . C o p e ,1889:662.

Glyptodon rivipacis Hay, 1923:40 [nomen n u d u m ] .Boreostracon flondanu s S i m p s o n , 1929b : 581 , fig. 1 0 . H o l m e s

and S i m p s o n , 1931:405, figs. 14-21 .Gazin , 1950:399 .Lunde l ius , 1972:36 , figs. 28-30, pi . 1.T Y P E S P E C I M E N S . A M N H 23547 (holotype),rear por t ion of carapace , inc luding pos ter ior bor de r ; A MN H 23548- 23562 ( pa r a t ypes ) , t opo t yp i -cal series of ca r apace por t i ons and isolated scutes.TYPE-LOCALITY.Semino le Field, Pinel lasC oun t y , F l o r i da (see Simpson, 1929b; Holmesand Simpson, 1931) .R E F E R R E D SPECIMENS.The following specim e n s are referred to G. floridanum (Simpson) .Type - Loca l i t y : A M N H 23514, sku ll f r agm en t( unseen); A M N H 23515 , two juveni le t ee th ;A M N H 23586 , i so l at ed s cu te s ; A M N H 23590,m a n d i b l e f r a g m e n t ; A M N H 9 5 7 2 6 - 9 5 7 2 8 , 14 isolated scutes.Cata l ina Gardens loca l i ty , Pinel las County ,

F l o r i d a : U F / F G S 6643 , com pl e t e ca r apace , pe l vis, six ante r ior cau dal ver tebra e , f ragm entarym a n d i b l e and five isolated teeth, and isolatedscutes .Mel bour ne , B r eva r d C oun t y , F l o r i da : U SN M256750, in "M elb ou rn e 1928" col lec tion, five isolated scutes.Sa r a so t a , m ou t h of Hog Creek, SarasotaC o u n t y , F l o r i d a : U S N M 11675, 11975, seven isolated scutes; from Sarasota County, local i t ies un

k n o w n : U F 1 1 4 9 5 , 3093, isolated scutes; from Sara so t a C oun t y , l oca l i t i e s unknow n: U F11495 ,3093 , i so la ted scutes ; UF/FSM 16830 i sola tedtooth ? N a

Orange County , Flor ida (exact loca l i ty unk n o w n ) : U S N M 11318, nea r l y com pl e t e m and i ble.

Waccasassa River , Levy County , Flor ida : UF/FSM 16379, 18455, two isolated scutes.

Mefford Cave II, M a r i o n C o u n t y , F lo r i d a : UF/FS M 652 5, e ight cara pacia l scutes.P i ney Po i n t , Mana t ee C oun t y , F l o r i da : UF/F S M 11469, one ca r apac i a l s cu t e , nea r an t e r i o rm a r g i n .Tomoka Par k , V o l us i a C ou n t y , F l o r i da : UF/

FSM 14762, one carapacia l scute .Ter ry Owen col lec t ion, Sarasota County , Flor i d a : U F / F S M 11498, one ca r apac i a l s cu t e .Pinel las County , Flor ida : Near br idge at T r e a sure Island fill , St. P e te r sb u r g: U F / F S M u n n u m bered, n ine carapacia l scutes ; R15E, T 3 0 S , appr ox i m a t e l y 35 carapacia l scutes ; 9th StreetS o u t h , St. P e t e r s b u r g , C a t a l i n a G a r d e n s : UF/F S M u n n u m b e r e d , two scutes.I nd i an R i ve r C oun t y , Wi n t e r B each , F l o r i da :U F / F S M 1677, isolated tooth from young indiv i dua l , N-.D eSot o C oun t y , Peace R i ve r , 1/2 mile nor thH i g h w a y 70, nea r A r cad i a : U F / F S M 19247 , ca r apac i a l f r agm ent , appr ox i m a t e l y 25 a r t i cu l a t edscutes.H endr y C oun t y , B anana C r eek , C a l oosa t cheeR i ve r , F l o r i da : U SN M 256751 , cauda l ve r t eb r a .Edis to Beach and Edingsvi l l e Beach, Col le tonC oun t y ( fo r m er l y C ha r l e s t on C oun t y ) , Sou t hC a r o l i n a : C h M - P V 2415, pos tg lenoid crania l

f r a g m e n t ; C h M - P V 2417, 2418, 2090, isolatedcarapacia l scutes .N ueces C ou n t y , Texas : A M N H 14158 , i so l at edscute , type specimen of Glyptodon petaliferus C o p e ,Wol fe C i t y , H un t C oun t y , Texas : U SN M 6071 ,

a p p r o x i m a t e l y 80 isolated scutes; two broken cranial fragments with N 2 and N 4 ; several isolatedtee th ; f ragments of mandible ; cervica l tube; f ragmentary dorsa l tube; pe lv ic an d scapular fragm e n t s ; six cauda l ve r t eb r ae ; two humer i , f ragm e n t a r y ; two ulnae; radius ; femur ; pa te l la ; t ib i ofibula; several foot bones.

A r ansas R i ve r nea r S i n t on , San Pat r ic ioC o u n t y , T e x a s : U S N M 11378, 11379, sevenscutes; TMM 31141-15, numerous scutes ; TMM31141-19, t ib iof ibula ; TMM 31141-3 , -16, -17,-48, cauda l ve r t eb r ae .

Ingles ide Pit, San Pa t r i c i o C oun t y , Texas :


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NUMBER 40 15

TMM 977-3 , incomplete carapace an d six anterior tail rings; TMM30967-2088, approximately50 articulated scutes from posterior region ofcarapace; T MM 30967-1926, nearly completepelvis and six caudal vertebrae; TMM 30967-1814, left mandible with Nj-Ng.

Bee County, Texas: TMM 31034-30, brokenmandible and isolated scutes; TMM 31186-19,isolated tooth.

Hawley, Jon es Coun ty, Texas: USNM 8644,approximately 15 isolated scutes.

Laubach Cave, Williamson County, Texas:TMM 41343, approximately 80 scutes.

Port Lavaca, Calhoun County, Texas: TMM41075-14, approximately 25 isolated scutes.

Runnels Pierce Ranch, near Whorton, Mata-gordo County, Texas: TMM 41530-6, three isolated scutes.

Specimens identified as Glyptothenum sp. cf. G.floridanum from Mexico are MWU 2246, fourcarapacial scutes in articulation and MWU 2247,2248 , isolated carapacial scutes, from Vera Cruz(Dalquest, 1961); and MWU 9732-9740, isolatedscutes from the Cedazo local fauna, Aguascal-ientes (Mooser and Dalquest, 1975). For otherrecords of Mexican glyptodonts, see discussionfollowing the distribution accounts.

A G E . R a n c h o l a b r e a n Land Mammal Age.DIAGNOSIS.Size intermediate to large; glenoid

fossa with distinct foramen; squamous occipitalsteeply inclined, with distinct median ridge; occipital condyles cylindrical; hypoglossal canalpresent, basioccipital-basisphenoid union contiguous, in same plane; foramen magnum inferiormargin deeply clefted; ventral extremity petro-mastoid crested; medial parietal region eitherelevated or smooth; mental foramen anterior toN i ; mandibular symphysis rounded and spoutlike; inferior margin of horizontal ramus of mandible flattened; posterior margin ascending ramusof mandible steeply inclined, not parallel to anterior margin; N2 trilobate; Ni ovoid, peglike,situated behind symphyseal curvature; Ng trilobate and submolariform, or bilobate and irregular; Ng molariform, posterior lobe convex andperpendicular, anterior lobe not squared; Nj fully

trilobate, transverse axes of lobes perpendicular,posterior face convex, sulcus on anterointernalface may be present; N5-N7 lobes nearly perpendicular; Ng anteromedial and anterolateral facesconvex, anterior apex blunt, anterior lobe widest,middle an d posterior lobes progressively narrower, posterior face weakly concave, slightlyoblique; cervical tube formed by vertebrae nos.2-6; axis articular facet oriented forward anddownward; dorsal tube formed by nine thoracicvertebrae, nos. 5-13 ; propodials and epipodialsintermediate in size and in exaggeration of features; humerus lacking supratrochlear foramen;articular facets of manus and pes flattened; eightto nine vertebrae in lumbar tube, three iliosacralvertebrae, three or four free vertebrae in sacralarch; two ischiosacral vertebrae; pubic crossbarsmall; ischiac crests posteriorly convergent; transverse processes of terminal sacral vertebra perpendicular to midline; anterior face of ilium uniformly concave; carapace large, probably highlyarched, divided into distinct preiliac and postiliacregions; carapace with at least some posteriorcurvature; scutes small in females with marginalsculpturing at suture; scutes large for males, without marginal sculpturing at sutures; central figures of scutes approximately equal in size toperipherals, usually slightly raised and weaklyconcave; anterior border scutes simple, lateralborder scutes conical; posterior border scutes offemales with pointed conical bosses; posteriorborder scutes of males bluntly conical; caudalarmor as in G. arizonae.

Glyptothenum cylindricum (Brown), newcombination

Brachyostracon cylindricum Brown, 1912:169 , figs. 1-4, pis. 16-18.T Y P E SPECIMEN.AMNH 15548, complete

carapace, 20 isolated teeth, atlas, hyoid fragment ,rib fragment, chevron, caudal ring fragment .

T Y P E - L O C A L I T Y . N e a r Ameca, Jalisco, Mexico.

R E F E R R E D SPECIMENS.Known from typespecimen only.


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16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGYA G E . R a n c h o l a b r e a n Land Mammal Age.DIAGNOSIS.Size large; N 1 weakly sigmoid; N

irregular, middle lobe internal border undeveloped, anterior lobe pointed at medial apex; N5-N~ anterior borders rounded, convex; N2 trilobate , submolariform; Ng molariform, posteriorlobe convex and perpendicular, anterior lobe notsquared; N5-N7 lobes nearly perpendicular; Nganterolateral and anteromedial faces convex, anterior apex blunt, lobes equally developed, posterior face concave, perpendicular; atlas free, alarprocesses laterally directed, no struts at anterioropening intervertebral foramina; posterior opening intervertebral foramina near midline; sevento eight vertebrae in lumbar tube; four iliosacralvertebrae; three free vertebrae in sacral arch; twoischiosacral vertebrae; pubic crossbar stout,united at symphysis; sacral arch compound curvepronounced; ischiac crests parallel; transverseprocesses of terminal sacral vertebra perpendicular to midline; ilium anterior surface stronglyconcavoconvex; carapace large, highly arched,divided into distinct preiliac and postiliac regions;carapace with cephalic boss; anterior borderscutes weakly bossed, lateral border scutes large,conical; posterior border scutes conical, centralfigures of scutes slightly greater than half thescute diameter, always slightly larger than peripherals, fiat to weakly concave; anterior andposterior apertures vertical in lateral profile.

Glyptothenum mexicanum (Cuataparo andRamirez), new combination

Glyptodon mexicanus C u a t a p a r o and Ramirez , 1875:362 , figs.1-4.

Brachyostracon mexicanus ( C u a t a p a r o and R a m i r e z ) . B r o w n ,1912:168, pis . 13-15.T Y P E S P E C I M E N . C a r a p a c e , skull, sacrum, and

isolated teeth (unseen), last known to be housedin the Mexico National Museum of Natural History; specimen number unknown.

T Y P E - L O C A L I T Y . D r a i n a g e canal in the Valleyof Mexico near Tequixquiac, Mexico.

R E F E R R E D S P E C I M E N S . K n o w n from typespecimens only.

A G E . R a n c h o l a b r e a n , presumably Wisconsinor Sangamon.

DIAGNOSIS .Carapace large, similar to that ofG. cylindricum; anterior teeth trilobate but lobesnot expanded.

STATUS OF Glyptothenum mexicanum (Cuataparoand Ramirez).The discovery of glyptodonts inNorth America was reported by two Mexicancivil engineers, who believed their specimen pertained to Glyptodon, but represented a distinctspecies that they named Glyptodon mexicanus (Cuataparo and Ramirez, 1875). Their description wasdeficient in several important respects, andBrown (1912) partially amended their descriptionof the carapace. The remaining skeletal parts,reportedly including the skull, mandible, teeth,and sacrum, had already been lost at the time ofBrown's study, but Brown did examine the carapace firsthand. Describing carapacial and skeletalremains of another specimen from a differentlocality as Brachyostracon cylindricus, Brown referredthe earlier named species to his genus. He included several photographs of the carapaces ofboth species. There is no doubt, as Brown asserted, that the two species belong in the samegenus, for the carapaces are nearly identical.Brown chose to retain B. mexicanus as a validspecies, claiming that it differs from B. cylindricusin dental and carapacial features. BrachyostraconBrown, 1912, is a junio r synonym oi GlyptothenumOsborn, 1903. Thu s the two Mexican species areGlyptothenumcylindricum (Brown) and G. mexicanum(Cuataparo and Ramirez). That the former isspecifically distinct from the other North American species is well established. Whether G. mexicanum is valid, however, is uncertain.

Apparently the type specimen of G. mexicanum,including the carapace, has been lost. If the species is valid, as assumed here, it will be necessaryfor future workers to designate a neotype, providing the type specimens are not located. By ourreten tion of the species it is hoped that futureworkers will recognize the type specimens if, andwhen, they should be found. Sinking the speciesin synonymy, or as a nomen dubium, would likely


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NUMBE R 40 17resul t in i ts being forgot ten. The fol lowing discuss ion out l ines the reasoning for i t s re tent ion.

First , i t is inco nce ivab le tha t the origina l descr ip t ion of the species is ent i re ly ina ccu ra te . T h es i ngu l a r ap pe a r a nce o f a g l yp t od on t ca r ap acean d skele ton is so un iqu e as to prec lude to ta lconjec ture , especia l ly by nonpaleontologis t s a t at i m e ( a cen t u r y ago) w hen g l yp t odon t s w er e unk n o w n i n N o r t h A m e r i c a , a n d w h e n c o m p a r a t i v em a t e r i a l w as unava i l ab l e . Mi s r ep r esen t a t i on o ft he ske l et on and ca r a pac e is und e r s t an dab l e , an dtheir inaccuracies are insufficient just i ficat ion forr educ i ng t he s t a t us o f G. mexicanum t o nom end u b i u m . Indeed, the i r descr ip t ion of the carapace, except for i l lustrat ing i t in reverse end-to-end or ienta t ion , seems accura te . Even the i r measu r em en t s fo r t he ca r apace , bo r ne ou t by B r ow n,are reasonable and they cor respond c lose ly to thec a r a p a c e o f G. cylindricum.

Because a t l eas t the descr ip t ion of the carapacew as accur a t e , t he r em a i n i ng por t i on o f t he i r de scr ip t ion should a l so be cons idered as bas ica l lycor rec t even though i t may be er roneous in de ta i lo r i n t e r p r e t a t i on .

Par t of the dubious s ta tus of G.mexicanum centers around the descript ion of i ts skul l . As Brown(1912) pointed out , the measurements g iven byC u a t a p a r o a n d R a m i r e z a re r e m a r k a b l e , i n d ic a t ing an ext remely prolonged skul l . Brown compared the shape of the skul l as figured in theor ig ina l descr ip t ion wi th tha t of the armadi l logenus Eutaetus. Th i s is ce r t a in l y an app r opr i a t ecom par i son , a l t hough com par i son w i t h t he sku l lo f a ch l am yt he r e w ou l d have been even m or eappr opr i a t e . I t now seem s p r obab l e t ha t C ua t apa r o and R am i r ez desc r i bed a com pos i t e o f aglyptodont skul l , proper ly be longing wi th theca r apace , and a ch l am yt he r e sku l l , f r om t he s am edepos i t , which may account for much of theconfus ion regarding th i s species .

Point ing toward the inc lus ion of por t ions of ach l am yt he r e sku l l a r e t he d r aw i ng , s eve r a l m ea su r em en t s , an d pa r t o f t he desc ri p t ion . C om par i son of the drawing in res tora t ion (Cuataparo andR am ire z, 1875, fig. 1) with th e i l lustrat io ns pro vided by Ja m es (1957) for a ch lam yth ere skul l

reveals a close similarityespecially James ' f igure2 i s remarkably s imi lar . Even the casque scutestha t James i l lus t ra ted show a c lose resemblance .The poss ib i l i ty of the presence of a chlamythereskul l among the or ig ina l mater ia l of G. mexicanumis a lso i nd i ca t ed by ce r t a i n m easu r em e n t s , am on gwhich the 174 mm length of the tooth row, l i s tedby the or ig ina l authors , cor responds c lose ly to the170 m m l eng t h t ha t J a m es ( 1957) r epor t ed . T hesef igures a re approximate ly equal to the tooth rowlength of Glyptothenum texanum; they are grea tert h a n G. floridanum and less than G. arizonae ( Tab l e s3 - 6 ) .

Mor eove r , t he cons t r uc t i on o f t he descend i ngprocess of the zygomat ic a rch f igured by Cuat apa r o and R am i r ez fo r G. mexicanum does notcor respon d wi th tha t of any othe r known g lyptodont . As f igured , the zygomat ic a rch of G.mexicanum is pos ter ior ly ope n, ra th er tha n com ple te as in o ther g lyptodonts . The doubly curveddescending process in the figured skul l bears asca l loped pos ter ior out l ine , and i t s basa l connect ion wi th the hor izo nta l ra m us is weak. T hisshape and cons t ruc t ion c lose ly resemble the uppersurface of the zygomatic arch in chlamytheres(see Ja m es , 1957, fig. 2 for com pa riso n) . H en ce ,the re is a dist inct possibi l i ty that th e zy go m atica r ch o f a ch l am yt he r e sku ll ( unkno w n t o C u a t a pa r o and R am i r ez ) w as t aken a s t he de scend i ngprocess of a glyptodont skul l .

The ev i dence ou t l i ned above suppor t s t he pos s ib i l i ty tha t a chlamythere skul l was associa tedw i t h t he g l yp t odon t ca r apace and w as e r r o neous ly f igured as pe r ta in ing to G. mexicanum bythe or ig ina l authors . On the o ther hand, the fac t sthat they l is t only eight teeth per tooth row(ra ther than nine , as in chlamytheres) , and tha tthey figured and described what are obviouslyg l yp t odon t , r a t he r t han ch l am yt he r e , t ee t h i nd i ca te tha t there was indeed a g lyptodont skul l orskul l fragments in the same col lect ion. Indeed, i tis poss ib le tha t po r t ions of the chla m yth ere an dglyp todo nt skull s were inadve r tent ly m ixed in ther e s t o r a t i on , and t he o r i g i na l au t hor s , unaw ar e o fch l am yt he r es bu t know i ng o f g l yp t odon t s , be -


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18 S M I T H S O N I A N C O N T R I B U T I O N S T O P A L E O B I O L O G Yl ieved that al l of these remains belonged

17286893 glyptodonts of north america

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