A new species of Zangerlia (Testudines: ) from the Upper redbeds at Bayan Mandahu, Inner Mongolia, and the relationships of the

Donald Brinkman and Jiang-Hua Peng

Abstract: Zangerlia neimongolensis sp.nov. is described on the basis of material from the Upper Cretaceous redbeds at Bayan Mandahu in Inner Mongolia. Zangerlia neimongolensis is similar to Zangerlia testudinimotpha in the proportions of the carapace and plastron and presence of a knob at the posterior end of the neural series, but differs from it in the arrangement of scutes covering the bridge. The placement of Zangerlia in the Nanhsiungchelyidae is supported by derived features of the bridge peripherals and plastral scutes shared by 2. neimongolensis, , and Nanhsiungchelys. These are the presence of ventrally expanded sixth inframarginal scutes, humeral scutes that are narrow at the midline and expanded laterally, pectoral scutes that are wide at the midline and narrow laterally, and large rectangular abdominal scutes. The skull of Zangerlia is more primitive than that of Nanhsiungchelys, the only other member of the family for which a skull is known. It shows extensive emargination of the temporal and cheek regions and the absence of a large, tubular external narial opening. A cladistic analysis of the Trionychoidea using Zangerlia as the representative of the Nanhsiungchelyidae suggests a sister-group relationship between the Nanhsiungchelyidae and .

RCsumC : Nous dkcrivons Zangerlia neimongolensis n.sp. a partir de vestiges rCcupCrCs dans les couches rouges d'lge CrCtacC tardif, a Bayan Mandahu, Mongolie intCrieure. Les proportions de la carapace et du plastron et la prCsence d'une protubkrance I'extrCmitC postCrieure de la sCrie neurale de 2. neimongolensis sont similaires i ce qu'on observe chez Zangerlia testudinimotpha, mais il y a des diffkrences quant i la disposition des plaques qui recouvrent le dos. Le classement de Zangerlia parmi les NanhsiungchClyidCs est fond6 sur les caractkres dCrivCs des plaques pCriphCriques du dos et les Ccailles du plastron ventral communes i Z. neimongolensis, Basilemys et Nanhsiungchelys. Leur plastron ventral est formCe de six Ccailles inframarginales, d'Ccailles humCrales Ctroites au centre du plastron et s'klargissant For personal use only. lateralement, d'tcailles pectorales larges au centre du plastron se rCtrtcissant latkralement et de larges Ccailles abdominales rectangulaires. Le crsne de Zangerlia est plus primitif que celui de Nanhsiungchelys, seul autre membre de la famille dont le crlne a CtC CtudiC. Le crlne exhibe une Cmargination Ctendue des rCgions temporale et jugale, avec l'absence de grande ouverture tubulaire externe des narines. Une analyse cladistique des TrionychoidCs, utilisant Zangerlia cornrne reprCsentant des NanhsiungchClyidCs, suggCre une relation de groupe-soeur entre les NanhsiungchClyidCs et les AdocidCs. [Traduit par la rCdaction]

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 Received February 18, 1995. Accepted June 28, 1995. D. Brinkman.' Royal Tyrrell Museum of Palaeontology, P.O. Box 7500, Drurnheller, AB TOJ OYO, Canada. J.-H. Peng. Institute of Vertebrate Paleontology and Paleoanthropology, Academia Sinica, P.O. Box 643, Beijing 100044, People's Republic of China. ' I Corresponding author (e-mail: [email protected] .ab. ca) . Can. J. Earth Sci. 33: 526-540 (1996). Printed in Canada / Imprim6 au Canada Brinkrnan and Peng 527

Pet$epa~ Zangerlia neimongolend sp.nov. onacrmaeTcR Ha ocHose MaTepaana a3 KpaCHOqBeTHbIX nnaCTOB B Eafi~~MaHAaXY BO BHYTP~HH~~~MoH~o~MH. Zangerlia neimongolensis cxoma c z. testudinimorpha B oTHomeHaa nponopqan KapanaKca a nnacTpoHa a npacyTcTsaR 6yrop~aB san~e~ Koaqe AopcanbHoro pHgar HO OTnaYawrcR pacnonoxeaseM CKYTOB, noKpHsamuax MocTnK. noMeueaae Zangerlia B ~anhsiungchelyidae nOATBepXAaeTCR yHaCnenOBaHHbIMI-3 XapaKTepHCTHKaMH nepa@epasec~ax neperoponoK (cen~)a nnacTpanbHbIx CKYTOB, 064ax An2 Z.neimonqolensis, Basilemys, B Nanhsiungchelys. T~KoBMM~RBnmoTcs npHCyTCTBHe BeHTpaJIbHO BHCTynaKluHX UeCTbIX HH&XLM~~~HH~~~H~IX CKYTOB, nneYeBMX uHTKOB, KOTOpbIe RBnHKlTCR y3KHMI-I B cpen~efinHHaH a pacuapeHHmMa naTepanbso, neKTopanbHMx CKYTOB, KoTopHe mapoKae B cpen~ennaHaa a ys~aenaTepanbao, a 6onbwax npxMoyronbHMx a6no~a~anb~b1xCKYTOB. Yepen Zangerlia 6onee npn~a~a~~anno CpaBHeHPiH3 C Nanhsiunqchel~,eAHHCTBeHHMM ApyraM YneHOM C~M~~CTB~, AnR KOTOpOI'O H3BeCTeH Yepen. OH HeMOHCTPWpYeT CYILleCTBeHHYD BbIeMYaTOCTb BHCOYHHX E-3 WeYHbIX o6nac~efia OTCyTCTBMe 60nbuoro Tpy65~aTor0BHemHerO HO3ApeBOOrO OTBepCTE'iR. AHanE33 KnaAOreHe3a Trionychoidea, nonbsy~cbZangerlia KaK npeAcTaBaTeneM Nanhsiungchelyidae, npeAnonomaTenbHo no~a3a~ae~cecTpaHcKo- For personal use only. rpynnoBoe ~saw~oo~~ome~aeMexqy Nanhsiungchelyidae a Adocidae. [nepeaon BbrnonHeH nnH penaKgm Hayq~o-Mccneno~arenbc~~eXyp~anbr]

Introduction of the family. This was followed by Mlynarski (1976), who The Upper Cretaceous redbeds at Bayan Mandahu in Inner included these features in the diagnosis of the Dermatemy- Mongolia have yielded a diverse assemblage of fossil ver- didae. However, the presence of inframarginal scutes is a tebrates that is, in general, similar to that from the Djadokhta primitive character state within the Eucryptodira and dermal Formation in Mongolia (Jerzykiewicz et al. 1993; Dong sculpture varies among taxa included within the Dermatemy- 1993; Dong and Currie 1993). However, remains are didae, so the placement of Zungerlia in the family is only much more abundant in the Bayan Mandahu locality. In con- weakly supported at present. trast to the two fragmentary turtle specimens collected in the Meylan and Gaffney (1989) used derived features to Djadokhta Formation of Mongolia (Gilmore 193I), seven resolve the relationships of many of the placed in substantially complete shells have been collected at Bayan the by Mlynarski (1976). The family was Mandahu. Many are associated with postcranial elements, restricted to the genera Dermatemys and Baptemys and was and two include cranial remains. This material is herein placed with the ~inosternidaein the ~inosternoidae.Zunger- described as Zungerlia neimongolensis sp.nov. lia was united with Basilemys and Nanhsiungchelys in the

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 The genus Zungerlia was erected by Mlynarski (1972) for Nanhsiungchelyidae, and this family was placed with a large, terrestrial turtle from the "Lower Nemeget Beds" and the ~rion~chiawithin the ~rion~choidea.A sister-group of Mongolia (now the Barun Goyat Formation, Jerzykiewicz relationship between the Nanhsiungchelyidae and Peltochelys and Russell 1991). Mlynarski placed Zungerlia in the Der- plus was supported primarily by features from matemydidae, because of the presence of inframarginal scutes the skull of Nanhsiungchelys. and dermal sculpture similar to that of some other members A close relationship between Basilemys and Nanhsiung- Can. J. Earth Sci. Vol. 33, 1996

Fig. 1. Zangerlia neirnongolensis, carapace and plastron. the Trionychoidea. It is concluded that Zungerlia is more (A, B) Type specimen, IVPP 020788-7, in (A) dorsal and closely related to Basilemys than is Nanhsiungchelys. A (B) posterior views. (C) Specimen IVPP 290690-6, in sister-group relationship between Adocus and the Nanhsiung- ventral view. chelyidae is suggested by the new information.

Institutional abbreviations IVPP, Institute of Vertebrate Paleontology and Paleoan- thropology, Beijing; NMB, Nei Mongo Bowuguan (= Inner Mongolia Museum), Hohhot, Inner Mongolia; TMP, Royal Tyrrell Museum of Palaeontology, Drurnheller .

Taxonomy

Order Cope, 1868 Suborder Eucryptodira Gaffney , 1975 Superfamily Trionychoidea Fritzinger 1876 Family Nanhsiungchelyidae Yeh, 1966 Genus Zungerlia Mlynarski, 1972

Diagnosis Shell relatively short and and wide compared with other members of the family; posterior peripherals subvertical in position, not flared outwards; first suprapygal much smaller than second; a knob present at about the position of the first suprapygal and the posterior edge of the shell steeply deflected below this; anterior lobe of plastron subrectangular in shape; posterior lobe short compared with other members of the family, distance between the posterior end of the plastron and posterior end of the carapace greater than the length of the posterior lobe of plastron.

Zangerlia neimongolensis sp.nov . (Figs. 1-9) For personal use only. Type specimen IVPP 020788-7, back half of shell, carapace preserved from the seventh neural, and plastron preserved posterior to hyoplastron-hypoplastron suture, skull, neck, girdles and limbs preserved within this portion of carapace, hind limbs and pelvis in articulation except for feet, remainder of skeleton disarticulated.

Locality and horizon Inner Mongolia, Nuchidaba locality, about 9 km northeast of chelys was also suggested by Sukhanov and Narmandakh Bayan Mandahu, which lies about 45 km north of Urad (1977), who synonymized the two genera and described the Houqi (Dong 1993; Eberth 1993). All the turtle specimens shell and limbs of a species from Mongolia, "Basilemys" collected from this locality come from a limited area within orientalis. Brinkman and Nicholls (1993) argued that this the Nuchidaba locality referred to as "the gate" (Eberth synonymy is not justified, and that the two Asian taxa are 1993), and are within Eberth's zone 2. Eberth interpreted both members of the genus Nanhsiungchelys. Nanhsiungchelys this zone as an organically productive, sandy area between orientalis is primitive relative to Basilemys in the retention the margins of an alluvial fan (zone 1) and a dune field of four inframarginal scutes. Only the axillary and inguinal (zone 3). scutes are present in Basilemys. Zungerlia was considered the most primitive member of the Nanhsiungchelyidae by Etymology Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 Brinkman and Nicholls (1993), because of the presence of The name is derived from Nei Mongol Zizhiqu, the province irregularly shaped inframarginals and the lack of a ventrally in which the Bayan Mandahu locality occurs. expanded sixth marginal scute in Zungerlia testudinimorpha. Information from Z. neimongolensis sp.nov. leads to a Diagnosis reappraisal of both the interrelationships of the genus within A species of the genus Zungerlia in which a midline keel is the Nanhsiungchelyidae and the position of that family within absent; the entoplastron is of large size and extends posterior Brinkman and Peng

Fig. 2. Zangerlia neimongolensis, carapace and plastron. (A, B) Type specimen, IVPP 020788-7, in (A) dorsal and (B) posterior views. (C) Specimen IVPP 290690-6, in ventral view. (D) Specimen IVPP 020790-5, in ventral view. AX, axillary scute; C8, eighth costal; GU, gular scute; IGU, intergular scute; ING, inguinal scute; M4-M6, marginal four to marginal six; N8, eighth neural; P6-Pll, peripheral six to peripheral eleven; PY, pygal; SP2, second suprapygal. For personal use only.

to the level of the axillary notches; and the midline plastral Description and comparisons sulcus is highly sinusoidal on the posterior lobe. The carapace of Z. neimongolensis (Figs. 1, 2, 3B) matches Referred specimens that of Z. testudinimorpha (Fig. 3A) in proportions, being IVPP 020790-5, complete plastron, first dorsal vertebra, shorter and more nearly circular in outline than that of right first dorsal rib, rib head of first costal, and isolated Nanhsiungchelys or Basilemys (Figs. 3C, 3D). As in phalanges and carpals; IVPP 290690-6, back end of plastron Z. testudinimorpha, a knob is present at about the end of and carapace prepared in ventral view, both feet and tail the neural series, and the posterior edge of the shell is steeply preserved in articulation, scattered dermal ossicles around deflected below this (Figs. lA, 1B). A midline keel is absent both feet; IVPP 020790-4, posterior three quarters of cara- in Z. neimongolensis. A shallow depression runs along the pace prepared in dorsal view; IVPP 130790-1, posterior- mid-dorsal surface of the carapace in some specimens (e.g.,

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 lateral edge of carapace prepared in dorsal view; NMB 2802, NMB 2802), but this is interpreted as an artifact of preserva- shell, nearly complete except for anterodorsal surface, which tion, and the presence of a smoothly rounded carapace is has eroded away, skull with lower jaws sitting on visceral thought to be the normal condition for the species. surface of anterior lobe of plastron, skull roof missing; NMB None of the available shells preserve the nuchal bone or 4252, posterior half of carapace, hind limbs preserved in the anterior edge of the neural series. Of the neural series, articulation but feet disarticulated and scattered. only the last two neurals can be distinguished (Fig. 2A). Both Can. J. Earth Sci. Vol. 33, 1996

Fig. 3. A comparison of the plastron of (A) Zangerlia testudinimorpha, (after Mlynarski 1972), (B) Zangerlia neimongolensis (from specimen IVPP 020790-5), (C) Nanhsiungchelys orientalis, (after Sukhanov and Narmandakh 1977), and (D) Basilemys variolosa (from Langston 1956). For personal use only.

are relatively short, rectangular elements. These completely similar to those of Basilemys and Nanhsiungchelys, although separate the costal bones. the posterior peripherals do not flair outwards as they do in The first suprapygal is intermediate in size between the those taxa. second suprapygal and last neural (Figs. 2A, 2B). The second The vertebral scutes are narrow, as in all other members is a large, wide triangular element extending laterally to contact of the family. The proportions of the pleural scutes do not the tenth peripheral. The pygal is a short, rectangular element. differ significantly from those of 2. testudinimorpha. The This arrangement of the posterior neurals and suprapygal- pleurornarginal sulcus follows the costal-peripheral suture pygal series is similar to that of 2. testudinimorpha. from peripherals seven to ten, then crosses the lower third of The first two costals are not preserved. The third to sixth the second suprapygal. costals are relatively narrow elements with little expansion of The plastron is best represented by IVPP 020790-5 either medial or lateral ends. The seventh and eighth costals (Fig. 2D). The surface of the bone is well preserved, and are both subrectangular but with their lateral ends slightly most sutures and sulci can be clearly identified. Areas of

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 wider than their medial ends (Figs. 2A, 2B). uncertainty, principally on the posterior half of the plastron, Only the seventh and more posterior peripherals are pre- are documented by specimens IVPP 290690-6 (Fig. 1C) and served in dorsal view (Figs. lA, 2A, 2B). The seventh to IVPP 020788-7 (Fig. 2C). tenth peripherals are tall and narrow, their height being about The anterior lobe of the plastron is subrectangular, in con- one and a half times their width. The height of the eleventh trast to Nanhsiungchelys and Basilemys, where the anterior peripheral is about equal to its width. These proportions are lobe is more triangular in shape (Figs. 3C, 3D). The pos- Brinkman and Peng

Fig. 4. Zangerlia neimongolensis, skull, type specimen, IVPP Fig. 5. Zangerlia neimongolensis, skull, type specimen, IVPP 020788-7, in (A) dorsal, (B) palatal, and (C) lateral views. 020788-7, in (A) dorsal, (B) palatal, (C) lateral, (D) anterior, and (E) occipital views. F BS, foramen basisphenoidale; F PO, fenestra postoticum; F POST CAN CAR, foramen posterior canalis carotici interni; F ST, foramen stapedio-temporalis; PR TR OT, processus trochlearis oticum.

terior lobe is generally shorter than wide, has a rounded

For personal use only. outline and is separated from the posterior edge of the cara- pace by a distance about equal to the length of the posterior lobe (Fig. 2C), matching the posterior lobe in Z. testudini- rnorpha (Fig. 3A) in proportions. However, some variation is present. In IVPP 290690-6, the posterior lobe is relatively longer and is more nearly rectangular in shape (Fig. 1C). The bridge is much longer than either of the plastral lobes. The epiplastra form much of the anterior lobe of the plas- 020790-5 (Fig, 2D). The in~ergularscures are large paired tron and have a long sutural contact with one another at the scutes that extend onto the anterior tip of the entoplastron. midline (Fig. 2D). The entoplastron is a large element, wider The pular scutes meet one another at the midline, formins a than long, that extends posterior to the level of the axillary narrow band that separates the intergular and hurneral scutes. notches (Fig. 2D). Both Nanhsiungchelys and Basilemys This is a derived feature. differing from that or Nanlrsiung- also have a large entoplastron wider than long, although chelys (Fig. 3Cj and two species of Bf~silernys(B. variolosa it does not extend as far posteriorly in these genera. An and R. rlohilis) where the gulars are trian_gular elements entoplastron was not preserved in Z. testudinimopha, but restricted to the anterolateral edges of the epiplastra. How- Mlynarski (1972) noted on the basis of the preserved portion ever. Rosil~n~vssinuo,~a (Fig. 3D) and Bnsilernys prueclnra of the hyoplastron that it was at most a small element. The are similar to Zclngrrlia in having gular scutes that contact hyoplastron-hypoplastron suture is located midway between onc another at the midline. the axillary and inguinal notches. The hyoplastron contacts The gencral arrangement of the more posterior scutes peripheral three anteriorly and extends to the anterior corner (Figs. IC, X,2D) conforms closely with that of other mem- of peripheral six posteriorly. The hypoplastron extends to hers of the Nanhsiungchefyidae. The hurneral scutes are the anterior tip of peripheral eight. The hypoplastron- narrow at the midline and cxpand laterally. They contact the Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 xiphiplastron suture extends transversely across the base axillary scute. preventing exposure of the pectoral scutes on of the posterior lobe of the plastron, rather than being rhe axillary notch. The pectoral scutes are wide at the midline V-shaped, as in primitive eucryptodires such as Ordosernys and narrow laterally. They cnntact the inguinal and Lfth (Brinkman and Peng 1993~). rnarpinal scutes laterally. The abdominal scutes span the The plastral scutes are most completely preserved in IVPP hyoplastron-hypplastron suture and cover a rectangular Can. J. Earth Sci. Vol. 33, 1996

Fig. 6. Zangerlia neimongolensis, lower jaws, type specimen, Rather, the inguinal scute contacts the femoral scute. A IVPP 020788-7, in (A) lateral and (B) dorsal views. DENT second inframarginal scute is absent, in contrast to the condi- POCK, dentary pocket; FO MECK, fossa meckelii; PR tion in Nanhsiungchelys (Fig. 3C). However, a third infra- COR, processus coronoideus. marginal may be present as an individual variant. On the right side of specimen IVPP 020790-5 (Fig. 2D), the pres- ence of this scute is indicated by traces of a suIcus between the sixth marginal and the abdominal scutes. The shape and position of this scute are similar to the third inframarginal of Nanhsiungchelys (Fig. 3C). However, no other specimen shows traces of such a scute, so the presence of a third infra- marginal scute may be variable within Z. neimongolensis. The marginal series is dominated by the sixth marginal, which is ventrally expanded as in Basilcmys and Nanhsiung- chdys. The fourth and fifth marginal scutes are visibIe on the left side of IVPP 020790-5 (Fig. 2D). The fourth is retracted and does not make contact with the pectoral scute. Zangerlia testudinimopha differs from 2. neimongolensis in that the infrarnargind scutes are irregularly developed and the right side does not match the left. Likely, as noted by MIynarski (1972), the scutes on the bridge area are abnor- mally developed in 2. testudinimolpha, and do not represent a primitive pattern for the genus, as assumed by Brinkrnan and Nicholls (I 993). The skull is best preserved in specimen NPP 020788-7 (Figs. 4, 5). As in Adocus, Baptem~s,and Dennatemys, and in contrast to Nanhsiungche(vs, deep temporal and cheek ernarginations are present. The temporal emargination reaches forwards to the posterior edge of the orbit. and thus is rela- tively longer than in Adocus, which ends relatively more posteriorly. The cheek emargination reaches above the ven- tral edge of the orbit, although the bar separating the cheek emargination from the temporal ernargination remains rela- tively deep compared with that of Adocus. The depth of this bar in Zangerlia is about half the vertical distance from the

For personal use only. quadrate articular surface to the edge of the temporal ernargi- nation. In Adocus the bar is about a third of this distance. The antorbitat region of Zangeriia does not project for- ward as a tubular snout as it does in Nanhsiringchelys. Rather, area on the ventral surface of the plastron. The femoral the external nard opening is a relatively small opening nearly scutes span the hypoplastron-xiphiplastron suture. cover round in end view and vertical in lateral view, as in Adocus. the base of the posterior Iobe of the plastron, and contact The opening is bordered ventrally by the paired premaxilla, the inguinal scute laterally. The anal scutes are V-shaped, laterally by the maxitlae, and dorsally by the prefrontal. The pointing forwards, but do not reach the hypoplastron- contact between the prefrontal and maxilla meets the narial xiphiplastron suture. The midline sulcus is straight from the opening midway along its side. Notches are present on either anterior tip of the plastron to about the base of the posterior side of the opening at the prefrontal-maxilla suture. lobe of the plastron. The sulcus cannot be traced completely Both Zangerlia and Adocus have a wide interorbital region, on the posterior Iobe, but at least two wide loops are present. with little embayment of the skull roof between the orbits. A Thus the sulcus in this region is, in general, similar to that groove on the external surface of the maxilla borders the of N, orientalis, B, praeclara, and B. nohilis in being highly anteroventral edge of the orbit in Zangerlia. No such groove sinuous, Jthough the number of loops and their full lateral is present in Adccus. The jugal forms much of the posterior extent is uncertain. In 2. restudinirnorpha the sulcus is nearly border of the orbit. The prefrontal forms the anterodorsal straight, and in B. varioIosa the sulcus is only weakly sinuous. edge and extends well posterior to the centre of the orbit, Sulci on the bridge area are incompletely preserved, suggesting that the ftontal was excluded from the margn so some uncertainty concerning the arrangement of scutes of the orbit. However, the anterior edge of the postorbital in this area exists. Following the pattern in Basilernys, as cannot be identified, so the relationships of the frontal, revised by Brinban and Nicholls (19931, a large scute prefrontal, and postorbital are uncertain. Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 covering the axillary notch is identified as the axillary scute, The otic capsule is anteroposteriorly elongate and bears a and a large scute covering the inguinal notch is identified sharply defined processus trochlearis oticum. The lateral as the inguinal smite. In Basilemvs, a narrow scute passes edge of the trochlearis is separated from the quadratojugal by between the inguinal and femora1 scutes to the posterior edge a distinct notch; the medial edge does not project forwards of the carapace. IVPP 290690-6 (Fig. 1C) demonstrates as sharply. This differs from the condition in Adocus where clearly that no such scute was present in 2. neimangolensis. both the medial and lateral edges of the processus trochlearis Brinkrnan and Peng 533

Fig. 7. Zangerlia neimongolensis, cervical vertebrae, type specimen, IVPP 020788-7. (A-G) Cervical vertebrae two to eight in lateral and dorsal views. (H) Cervical vertebra two in posterior view. (I) Cervical vertebra five in anterior view. (J) Cervical vertebra six in posterior view.

Fig. 8. Zangerlia neimongolensis, scapula and coracoid, type specimen IVPP 020788-7. (A, B) Right scapula in (A) posterior and (B) anterior views. (C, D) Right coracoid in (C) ventral and (D) dorsal views. For personal use only.

oticum are well defined and the process projects forward into magnum and the dorsolateral portion of the occipital con- the adductor fossa. It is uncertain whether the descending dyle. Two foramina nervi hypoglossi are present in the exoc- process of the parietal forms a portion of the trochlear surface. cipital just lateral to the occipital condyle. These foramina Only the medial edge of the foramen stapedio-tempsralis are floored by the basioccipital tubercula. The basioccipital is preserved. The diameter of this opening is slightly less than tubercula are wide structures weakly subdivided into a medial the diameter of the foramen posterius canalis carotici interni. portion formed by the basioccipital and a lateral portion The supraoccipital spine is long, deep, slightly thickened formed by the exoccipital. The basioccipital tubercles are ventrally, and has a rounded ventral edge. The squamosal separated from one another by a deep median trough in the spines are much shorter in length than the supraoccipital ventral surface of the basioccipital. spine, comparable to those of Adocus. The fenestra postotica is a nearly circular opening bor- Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 The occipital condyle is a low, wide structure formed dered dorsally by the opisthotic, laterally by the quadrate, by the basioccipital and exoccipitals. Unlike the condition medially by the exoccipital, and ventrally by the pterygoid. in most turtles, the basioccipital reaches the dorsal surface Meylan and Gaffney (1989, their Fig. 4) identify in Adocus of the condyle and forms the ventralmost border of the a foramen bordered by the exoccipital and basioccipital and foramen magnum. located medial to the foramen nervi hypoglossi as a foramen The exoccipitals form the lateral borders of the foramen jugulare posterius. However, the foramen jugulare posterius Can. J. Earth Sci. Vol. 33, 1996

Fig. 9. Zangerlia neimongolensis, forelimb elements, type posteriorly elongate, rather than nearly circular as in Adocus, specimen, IVPP 020788-7. (A-C) Right humerus in (A) dorsal, and the distance between the anterior edge of this cavity and (B) ventral, and (C) posterior views. (D, E) Right radius and the posterior edge of the orbit in Zangerlia is relatively less. ulna in (D) anterior and (E) posterior views. The triturating surface of Zangerlia is simpler than that of Adocus, Baptemys, and Dermutemys, in the absence of a maxillary tooth. A deep pit is present on the most anterior part of the triturating surface, which is formed by the pre- maxilla, suggesting the presence of a symphyseal hook on the dentary. As in Adocus, this pit is not bordered posteriorly by a commissual ridge, which in Baptemys and Dermutemys is a sharp transversely oriented ridge located just posterior to the symphyseal pit. A small opening at the base of this pit is in the position of the intermaxillary foramen of trionychids, but is interpreted as an artifact of preservation because it is irregular in shape. The triturating surface is widest lateral to the posterior half of the internal nares. At its maximum width, the triturat- ing surface is much narrower than in Adocus. Lateral to the internal nares, the lingual ridge is high and sharp. The internal nares are oval openings relatively wider than in Adocus and separated by a relatively wider internarial bar. The palatines roof the posterior end of the internal nares and extend lateral to them, reaching the medial edge of the tritu- rating surface. The palatines are not truncated anteriorly as they are in Nanhsiungchelys and members of the Trionychia, so the orbit has only a small area of exposure looking dorsally through the foramen orbito-nasale. The foramen palatinum posterius is preserved only on the left side of the skull. It is larger than in Adocus and differs in its position. In Zangerlia, the foramen is located between the palatine and pterygoid, the primitive position, whereas in Adocus, Baptemys, and Dermatemys the foramen palatinum posterius is surrounded entirely by the palatine. The processus pterygoideus externus, preserved only on the left side of the skull, is longer than For personal use only. in Adocus and does not have as strongly concave a pos- terior edge. The foramen posterius canalis carotici interni is located entirely within the pterygoid well anterior to its posterior edge. A large foramen basisphenoidale is present between the basisphenoid and pterygoid, a feature that Brinkman and Nicholls (1993) interpreted as primitive for eucryptodires and equivalent to the foramen carotico-pharyngeale of Chrysemys (Albrecht 1967). Poor preservation of the bone in this area prevents identification of the canalis caroticus lateralis or canalis caroticus internus, both of which should be visible within the foramen basisphenoidale. The basisphenoid has only a small area of exposure on the palate. The small size of ventral exposure of the basisphenoid and its rectangular shape differ from the condition in Adocus, where the basisphenoid is large and triangular in ventral view. The lower jaws, present in specimen IVPP V020788-7 is typically lateral to both the foramen nervi hypoglossi and (Fig. 6), are incompletely preserved, the postdentary portion the exoccipital, so the foramen jugulare posterius of Meylan of the right ramus is missing, and the articular is missing and Gaffney (1989) is likely one of the foramina nervi hypo- from the left. The triturating surface has a shallow dentary glossi. Thus reinterpreted, Zangerlia and Adocus would be pocket with a convex medial edge. This pocket opposed the

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 similar in the absence of a distinct foramen jugulare posterius sharp lingual ridge of the maxillary triturating surface. It is and in the position of the foramen nervi hypoglossi. possible that this edge is homologous to the maxillary tooth The quadrate of Zangerlia has a completely enclosed present in some other trionychoids. The coronoid process is incisura columella auris, as does that of all trionychids. A located at about the middle of the lower jaw and is lower than shallow, wide groove extends across the posterior end of the that of either Adocus or Baptemys. A large fossa meckelii is quadrate above the jaw joint. The tympanic cavity is antero- present posterior to the coronoid process. The articular is not Brinkrnan and Peng

preserved, so it is uncertain whether a retroarticular process being nearly horizontal. The coracoid (Figs. 8C, 8D) is a was present. Sutures cannot be identified with confidence. paddle-like structure sutured to the acromion process at an Cervical vertebrae two to eight are present in specimen acute angle. IVPP 020788-7 (Fig. 7), and the first thoracic vertebra is The humerus is short and strongly curved (Figs. 9A, 9C). present in specimen IVPP 020790-5. Numbers two to seven The humeral head is oval in end view. The greater trochanter are opisthocoelous. Cervical eight is biconvex. The articula- (medial process) of the humerus is much larger than the tion between the sixth and seventh vertebrae is doubled, lesser trochanter (lateral process), and is directed only slightly although the two surfaces are continuous. The articulations lateral relative to the long axis of the humerus. The distal between the seventh and eighth vertebrae and between the articular surface is narrow and faces strongly ventrally. eighth cervical and first thoracic are doubled, and the two The radius and ulna (Figs. 9D, 9E) are short, about half surfaces are separated from each other. Adocus differs in the length of the humerus. Both elements are nearly straight. that the eighth cervical is opisthocoelous and has a single The ulna is a massive bone, with little constriction of the articular surface posteriorly. shaft region. The proximal articular surface is triangular Centra two to seven are relatively long. Centrum eight in proximal view, with a well-developed olecranon process. is much shorter, less than half the length of the preceding The radius has a rounded, concave proximal end, and an centrum. expanded, flattened distal end. The axis has a sharp mid-ventral ridge. The more pos- The pelvis of IVPP 020788-5 is preserved in place, but is terior vertebrae each have a well-defined keel that extends exposed in ventral and anterior view. The dorsal blade of the ventrally as a narrow plate of bone (not preserved on the ilium is tall but not greatly expanded. Undescribed pelvic fourth centrum). On centrum three, this keel extends the full elements of Basilemys (e.g., TMP 82.19.231) show that length of the centrum. More posteriorly the keel becomes the ilium had a similar structure in that taxon. The ventral relatively shorter, and by centrum six the keel is restricted plate of the pelvis is short and wide. The thyroid fenestra is to the anterior portion of the centrum. In contrast to Adocus, large and not divided by a pubis-ischium contact at the where the ventral keel of the eighth centrum is thickened and midline. The ischium forms a nearly vertical plate, with has small accessory keels on either side of the mid-ventral the metischial processes reduced to thickened rugose areas keel, only a single, unthickened keel is present in Zangerlia. projecting only slightly posteriorly from the vertical plate. Neural spines are not present on any of the cervical centra, The pubis is composed of two portions, a lateral pillar formed although the axis has a mid-dorsal ridge extending the length by the acetabular portion and the pectineal process, and a of the neural arch. The zygapophyses of all the cervicals are triangular ventral plate that meets its fellow along the mid- strongly divergent, forming an X in dorsal view. The length line. The pectineal process is stout, being nearly circular in of the neural arch measured mid-dorsally between the bases cross section. The ventral end of this process ends in a of the pre- and postzygapophyses decreases from the axis to rugose area that rested on the plastron. The ventral plate has vertebra six, then increases slightly. On centrum two to five, a weak suture with the opposite pubis at the midline. The the postzygapophyses emerge from the middle of the neural posterior portion of this plate is nearly horizontal, and the For personal use only. arch and extend nearly straight dorsolaterally. In cervicals anterior portion curves ventrally, so is nearly vertical. six and seven, the postzygapophyses originate from an increas- The femur (Fig. 1C) is sigmoidal, although slightly less ingly more anterior position and become increasingly more so than the humerus. The intertrochanteric fossa is deep and curved, leading to a massive hook-shaped structure on cervical bordered distally by a low ridge connecting the base of the eight. In lateral view, the postzygapophysis of cervical eight two trochanters. The distal end of the femur is wider than originates from an anterior position on the centrum and that of the humerus and does not project as far ventrally. incorporates most of the neural arch (Fig. 7G). However, as with the humerus, the articular surface faces Transverse processes are located below the prezygapo- ventrally and is divided into two distinct condyles. physis. These processes are of very small size on the axis, Little detail can be seen on the tibia. The fibula is a increase in size on vertebrae three to six, and decrease in size slender element, little expanded at either end. No trace on the more posterior vertebrae. The transverse process of of ridges or crests are visible on its shaft. the third vertebra is barely separated from the prezygapo- Well-preserved feet visible in ventral view are present in physis. On the fifth and sixth cervicals, the transverse process specimen IVPP 290690-6 (Fig. 1C). The tarsus includes a is a large structure that points ventrally. single astragalocalcaneum, as in turtles generally. Four toes The first thoracic vertebra is low and wide and has a are present, each with two phalanges. The basal phalanx is rounded ventral surface and ventrally facing concave prox- a short element, higher than it is long. Dermal ossicles are imal articular surfaces. The first thoracic rib is relatively scattered around the feet. As in Basilemys, these are conical short. It articulates with the first thoracic vertebra along the elements with a roughened surface. anterior half of the centrum. None of the remaining thoracic vertebrae are visible. Discussion Both right and left pectoral girdles are present in specimen

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 IVPP 020788-5. The scapular and acromion processes of Zangerlia neimongolensis and Z. testudinimorpha are similar the scapula meet at about right angles (Figs. 8A, 8B). The to one another but differ significantly from other members of scapular process is rod-like. The acromion process is flat- the Nanhsiungchelyidae (Nanhsiungchelys and Basilemys). tened and is bowed concave downwards. Also, the blade They have a relatively shorter carapace, with a short posterior of the acromion process is twisted, the base of the process plastral lobe, and the presence of a strong knob at the posterior being nearly vertical in cross section, and the distal end end of the neural series marking a change in slope from the Can. J. Earth Sci. Vol. 33, 1996

dorsal to the posterior edge of the carapace. The last two of midline and separate the intergular from the humeral scutes these features are considered to be uniquely derived for the is a derived feature shared with B. sinuosa and B. praeclara. genus within the Nanhsiungchelyidae. The anterior lobe of In the primitive condition, seen in N. orientalis, B. variolosa, the plastron, known only in Z. neimongolensis, differs from B. nobilis, and Adocus, the gulars are triangular scutes that that of Nanhsiungchelys and Basilemys in being rectangular generally do not extend onto the entoplastron and never meet in shape and in having a broad anterior edge. In Nanhsiung- on the midline. The similarities in the shape of the gular chelys and Basilemys, the anterior lobe is triangular in shape scutes in Zungerlia and Basilemys are interpreted as indepen- and the anterior edge is very narrow. Zungerlia is likely dently derived character states. primitive in this feature. In summary, the family Nanhsiungchelyidae is considered Zungerlia neimongolensis differs from Z. testudinimorpha to be a well-defined monophyletic unit on the basis of derived most significantly in the arrangement of scutes covering the features of the plastron and carapace. Within this family, bridge. The bridge marginals of Z. neimongolensis are similar Zungerlia is interpreted as the sister taxon to Basilemys and to those of Basilemys and Nanhsiungchelys in that the mar- they are, in combination, the sister group of Nanhsiungchelys. ginal~extend far ventrally onto the bridge, reaching a line connecting the inguinal and axillary notches. In all three the Phylogenetic position of the medial end of the sixth inframarginal is markedly expanded. Nanhsiungchelyidae Zungerlia neimongolensis is distinctive in that the fourth marginal scute is retracted, so does not contact the abdominal Previously, the only member of the Nanhsiungchelyidae scute. In Z. testudinimolpha, the marginals do not extend as represented by cranial material was Nanhsiungchelys. Sirni- far ventrally, the sixth marginal is not strongly expanded, larities in the skull of Nanhsiungchelys and the Trionychia and the inframarginals are irregularly developed. Since the suggested a sister-group relationship between these taxa rela- right and left sides of the shell of Z. testudinimolpha do not tive to Adocus (Meylan and Gaffney 1989). However, many match one another, this arrangement may be an individual of the characters that unite Nanhsiungchelys and the Triony- anomaly. However, in the absence of independent evidence chia are not present in Zangerlia. These include differences for this, the arrangement of the marginals and inframarginals in the degree of cheek emargination (well developed in in Z. testudinimolpha is considered an autapomorphic feature Zangerlia but weakly developed in Nanhsiungchelys and of that species. the Trionychia), the degree of reduction of the vomer (not Zungerlia testudinimolpha also differs from Z. neimon- reduced in Zungerlia but reduced in Nanhsiungchelys and golensis in the size of the entoplastron, the sinuosity of the the Trionychia), and in development of the processus ptyery- midline sulcus, and the absence of a midline carapacial keel. goideus externus (present in Zungerlia, reduced or absent in The entoplastron of Z. testudinimorpha was not preserved, Nanhsiungchelys and the Trionychia). In all these features, but based on the hyoplastron, Mlynarski (1972) concluded the condition seen in Zangerlia is interpreted as primitive for that it is at most a small element. In Z. neimongolensis, the the family Nanhsiungchelyidae. In order to evaluate the entoplastron is a large pentagonal element that extends far phylogenetic significance of this new information the data set For personal use only. posteriorly. The midline sulcus in Z. testudinimorpha is used by Meylan and Gaffney (1989) was modified by includ- straight or at most weakly sinuous on the posterior lobe of ing Zangerlia in place of Nanhsiungchelys and Basilemys. the plastron. In Z. neimongolensis, the midline sulcus on the Zangerlia was used as the sole representative of the family posterior lobe of the plastron is highly sinuous. A mid-dorsal Nanhsiungchelyidae because it was assumed that within the keel is present in Z. testudinimolpha, whereas Z. neimon- family it retained the primitive states of the characters used. golensis has a rounded dorsal surface or possibly a shallow This will be tested in the future by information from the groove running along the mid-dorsal surface of the shell. In skull of Basilemys that is currently under study (Canadian all these features, Z. neimongolensis is similar to Nanhsiung- Museum of Nature specimen NMC 8890). In addition, chelys and at least some species of the genus Basilemys. Thus recently published information on the structure and relation- these character states are interpreted as primitive for both the ships of primitive eucryptodires has provided a more detailed genus Zangerlia and the family Nanhsiungchelyidae. understanding of the outgroups appropriate for interpreting Zangerlia is derived relative to Nanhsiungchelys and similar the polarity of character states within the Trionychoidea. In to Basilemys in the loss of the second inframarginal, absent particular, Peng and Brinkman (1994) argued that Xinjiang- in both Z. neimongolensis and Basilemys. Zungerlia is primi- chelys is more closely related to the Centrocryptodira, a clade tive relative to Basilemys in the presence of a large third mar- including all living cryptodires, than is . Further, ginal scute in at least some individuals, and in the absence Brinkman and Peng (1993a, 1993b) argued that within the of a narrow extension from the posterolateral corner of the Centrocryptodira the macrobaenids, such as , and abdominal scute between the inguinal and femoral scutes to the sinemydids, such as , are the most primitive the inguinal notch. This extension has a sulcus separating it known taxa. Thus these taxa are here used to reevaluate the from the abdominal scute in B. variolosa (preserved in speci- polarity of character states within the Trionychoidea. men TMP 94.666.28), but not in B. praeclara (Brinkman The revised list of characters and their states is given in

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 and Nicholls 1993). We consider the B. praeclara condition Table 1. The polarity of four characters was revised. These to be primitive for the genus, and identify the narrow scute are character 3 (foramen posterius canalis carotici interni between the inguinal and femoral scutes as an extension of completely surrounded by pterygoid), character 14 (scutes the abdominal scute. The presence of this feature is inter- sulci of skull roof), character 29 (plastron strongly sutured preted as an autapomorphic character of Basilemys. to carapace at bridge), and character 42 (cheek emargination The presence of band-shaped gular scutes that meet on the reaches level of orbit). Brinkman and Peng

Table 1. Characters and character states used in the analysis of relationships of the members of the Trionychoidea. Character state

Character n 1 2

1. Foramen stapediotemporale Large Small Absent 2. Size of foramen caroticum laterale FCL = FACCI FACCI > FCL FCL > FACCI (FCL) relative to size of foramen anterius canalis carotici interni (FACCI)* 3. Foramen posterius canalis carotici Yes interni ventral in position and completely surrounded by pterygoid 4. Basis tuberculi basalis Present Absent 5. Maxillary "tooth" Absent Present 6. Commissural ridge Absent Present 7. Premaxillae fused No Yes 8. Foramen intermaxillaris Absent Present 9. Vomer reduced No Yes 10. Palatine truncated anteriorly No Yes 11. External process of pterygoid Present Absent 12. Basisphenoid - palatine contact Absent Present 13. Incisura columellae auris closed No Yes 14. Scutes sulci of skull roofing bones Absent Present 15. Skull roofing bones sculptured No Yes 16. Frontal bones enter orbit Yes No 17. Maxilla contacts quadratojugal No Yes 18. Retroarticular process Absent Present 19. Three keels on carapace No Yes 20. Neural formula: No Yes 6>4<6<6<6<6 21. Costal bones meet on the midline Yes No 22. Number of peripheral bones* 11 per side 10 per side 9 or fewer per side 23. Transverse processes of thoracic No Yes For personal use only. vertebra 9 sutured to overlying costal 24. Axillary buttress of hyoplastron No Yes reaches overlying costal bones 25. Rib ends strongly articulated to No Yes vertebral centra 26. Ventral process of eighth Single Double Absent cervical vertebra* 27. Number of suprapygals Two One None 28. Plastral kinesis present along No Yes anterior edge of hyoplastra 29. Plastron strongly sutured to No Yes carapace at bridge 30. Midline plastral scute No Yes sulcus sinuous 31. Gular scales (set 2) Present Absent 32. Pectoral scales (set 4) Present Absent 33. Pectoral scales reach entoplastron No Yes 34. Abdominal scales (set 5) Meet medially Displaced medially Absent 35. Number of inframarginal scales 515 to 414 within one genus 414 to 313 within one genus 313 to 212 within one genus 36. Notch present in ilium just No Yes

Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 posterior to acetabulum 37. Thelial process Absent Present 38. Biconvex cervical Is number 4 Is number 3 Is number 2 39. Articulations between No Yes cervicals 2 -7 opisthocoelous 538 Can. J. Earth Sci. Vol. 33, 1996

Table 1 (concluded). Character state

Character 0 I 2

40. Phalangeal formula* 2-3-3-3-3 2-2-2-2-2 Shows hyperphalange 4 1. Paired ventral processes of Absent Present the nuchal 42. Cheek emargination reaches No Yes level of orbit 43. Coronoid tall and located near No Yes middle of mandible 44. Parietal contribution to the Absent Present processus trochlearis oticum 45. Costoperipheral sutures Present Absent 46. Shell scales* Present Absent from plastron Absent from carapace and plastron 47. Marginal scales reach cosal bones No Posteriorly only Posteriorly and laterally 48. Antrum postoticum reduced No Yes Note: The primitive condition, state 0, is determined by outgroup comparison using Xinjiangchelys, and primitive Centrocryptodira such as Ordosemys and Sinemys as outgroups. The states of those muitistate characters marked with an asterisk are not considered to form a transformation series and were run unordered. From Meylan and Gaffney (1989) with modifications as discussed in the text.

Table 2. Distribution of characters from Table 1 among the Trionychoidea.

Character No. :

1 2 3 4 Taxon 1234567890 1234567890 1234567890 1234567890 12345678

Outgroup 0000000000 0000000000 0000000000 0000000000 00000000 Adocus 00001OOOOO 0001000101 10?0000011 0010000?10 01110020 Zungerlia 0?0?000000 001???0?0? OOOOOOOO11 00102???1 1 ? 11?0010 Peltochelys ?????????? ????????00 01????0011 00001????? 1???0000 0?1?00??11 1110100?00 11001?110? ?????????? 10?111?1 For personal use only. Carettochelys 0101001 111 1110101 100 110011110? ?????00?10 101111?1 0101001111 1110000100 120012210? ?????00?12 001112?0 0101001 111 1110000100 120012210? ?????01?12 001112?0 Emarginachelys 001 1100000 0000000?00 00?0000000 11?0100000 01?00000 Baptemys 2201110000 0000000000 00?10?0010 11?0110100 01000000 Dermutemys 2211110000 0000000000 1001000010 11?0001200 00000000 Agomphus ?????????? ????????OO 00?00?0011 11?02????? 0???0000 Hoplochelys ?????????? ????????lo 00?00?0010 11?11????? 0???0000 1211000100 1000011010 0110011110 11?2210100 00000000 Kinostemon 1211000000 1000011010 1110011110 11?2210100 0001OOOO

The presence of a ventrally positioned foramen posterius Ordosemys and Sinemys) are without sulci on the skull roof. canalis carotici interni completely enclosed by the pterygoids Meiolaniids are an exception to this. is interpreted as a primitive character state, since it is present Using testudinoids as a sister group to the trionychoids to in both Xinjiangchelys (Kaznyshkin et al. 1990) and primi- interpret polarities, Meylan and Gaffney (1989) concluded tive centrocryptodires such as Sinemys (Brinkman and Peng that a strong sutural connection between the carapace and 1993b). Further, this interpretation is more consistent with plastron was the primitive character state and the loose con- the transformation sequence described by Rieppel(1980) and nection of trionychids and carettochelyids was interpreted as modified by Brinkman and Nicholls (1993) in which the most a derived character state within trionychoids. This inter- primitive stage is one in which the canalis caroticus internus pretation is reversed here, because both Xinjiangchelys and Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 is represented by a groove on the ventral surface of the ptery- macrobaenids have a loose connection between the carapace goid, and the most derived is one in which the canalis caroticus and plastron. internus opens on the dorsal surface of the pterygoid. The degree of emargination of the cheek region is not The presence of scute sulci on the skull roof is interpreted known in Xinjiangchelys, but in primitive centrocryptodires, as a derived character state, because most outgroups (e.g., such as Sinemys, Hangaiemys, and Dracochelys, the cheek Brinkman and Peng

Fig. 10. Cladograms showing the interrelationships of Xinjiangchelys is used as an outgroup. Since we accept that members of the Trionychoidae produced from data matrix in the Nanhsiungchelyidae is a monophyletic family on the Table 2. (A) A strict consensus of eight most parsimonious basis of scute characters not included in this data matrix and cladograms. (B) A majority-rule consensus of eight most that features of the skull of Zungerlia shared with Adocus are parsimonious cladograms. primitive for the family, Zungerlia is the only member of the outgroup family used in this analysis. I A phylogenetic analysis using the program PAUP 3.1.1 Adocus resulted in eight most parsimonious cladograms. A strict Zangerlia consensus of these (~ig.-lOA)agrees with a cladogram pre- Peltochelys sented by Meylan and Gaffney (1989) in the recognition of two major clades within the Trionychoidea, the Trionychoidae Anosteira and ~inosternoidae.The interrelationships of genera within Carettochelys the Trionychoidae differ in that the Nanhsiungchelyidae and Lissemys Adocus form a monophyletic clade. This relationship is sup- Trionyx ported by four unambiguous characters. These are 14 (scute sulci on skull roof), 20 (neural formula 6 >4 < 6 < 6 < 6 < 6), I Emarginachelys 33 (pectoral scales reach entoplastron), and 47 (marginal scales -Baptemys reach costal bones). However, only two of these, 33 and 47, Dermatemys are known in both Zungerlia and Adocus. Thus confirmation € from additional characters is necessary before this relation- -1- -1- Agomphus ship can be accepted as a robust phylogenetic hypothesis. 1- 1- Hoplochelys The relationships of Peltochelys, the Trionychia, and the Staurotypus Adocus - Nanhsiungchelyidae clade are unresolved in a strict consensus tree, although in a majority-rule consensus tree A (Fig. lOB), Peltochelys is united with the Trionychia as pro- posed by Meylan (1988) and Meylan and Gaffney (1989). outgroup The relationships of genera within the Kinosternoidae are largely unresolved in a strict consensus tree (Fig. lOA), but Adocus a majority-rule consensus tree (Fig. 10B) gives relationships Zangerlia that mirror those proposed by Meylan and Gaffney (1989), Peltochelys differing only in the position of Hoplochelys and Agomphus, both of which are represented by less than 50% of the charac- Anosteira ters in the data matrix. Carettochelys Thus, the additional information from Zungerlia and the For personal use only. reinterpretation of the polarity of some character states loo Lissemys presented here largely supports the cladogram proposed Trionyx by Meylan and Gaffney (1989). The primary difference is I ,--- Emarginachelys that the Nanhsiungchelyidae and Adocidae form a monophy- Baptemys letic clade rather than successive sister taxa to the Triony- chia. Additional characters will be necessary to corroborate Dermatemys this relationship. Agomphus Hoplochelys Acknowledgments Staurotypus The authors would like to thank Zhi-Ming Dong, Xi-Jin Kinosternon Zhao, Rong Li, Zhi-Lu Tang, Phil Currie, and Dale Russell for their leadership during the work in the Bayan Mandahu locality that led to the discovery of the specimens described is weakly emarginated. Thus a deep emargination reach- here, and the remaining participants of the Dinosaur Project ing the ventral edge of the orbit is interpreted as a derived (China - Canada - Alberta - Ex Terra) for making this a character state. memorable and successful field experience. We also greatly Character 39, all intercervical articulations opisthocoelous, appreciate the time and effort of Peter Meylan and Gene was redefined to intercervical articulations between cervicals Gaffney in reviewing this paper, which led significantly to two to seven opisthocoelous. This is because the character its improvement. distributions do not allow unambiguous interpretations as to whether or not the presence of a biconvex eighth cervical Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16 (also present in Ordosemys and Zungerlia) is primitive. References The data matrix for this revised list of characters and their Albrecht, P.W. 1967. The cranial arteries and arterial foramina of states is given in Table 2. The outgroup is based on Ordo- the turtle genera Chrysemys, , and Trionyx: a semys except for features of the anterior end of the plastron, comparative study with analysis of possible evolutionary which are not known in that genus. For these characters, implications. Tulane Studies in Zoology, 14: 81 -99. Can. J. Earth Sci. Vol. 33, 1996

Brinkman, D.B., and Nicholls, E.L. 1993. New specimen of Kaznyshkin, M.N., Nalyandyan, L.A., and Nessov, L.A. 1990. Basilemys praeclara Hay and its bearing on the relationships Middle and Late turtles of Fergana (Kirghiz SSR). of the Nanhsiungchelyidae (Reptilia: Testudines). Journal of Yszhegodnik Vsesoyuznogo paleontologicheskogo obshchestva Paleontology, 67: 1027 - 103 1. [Annual of the All-union Palaeontological Society], 33: Brinkman, D.B., and Peng, J.H. 1993a. Ordosemys leios, n.gen., 185 -204. (In Russian.) n.sp., a new turtle from the Early Cretaceous of the Ordos Meylan, P.A. 1988. Peltochelys Dollo and the relationships among Basin, Inner Mongolia. Canadian Journal of Earth Sciences, 30: the genera of the Carettochelyidae (Testudines: Reptilia). 2128-2138. Herpetologica, 44: 440 -450. Brinkman, D.B., and Peng, J.H. 1993b. New material of Sinemys Meylan, P.A., and Gaffney , E.S. 1989. The skeletal morphology (Testudines, Sinemydidae) from the Early Cretaceous of China. of the Cretaceous cryptodiran turtle, Adocus, and the relationships Canadian Journal of Earth Sciences, 30: 2139-2152. of the Trionychoidea. Novitates No. 2941. Dong, Z.M. 1993. The field activities of the Sino-Canadian Mlynarski, M. 1972. Zangerlia testudinimorpha n.gen., n.sp. a Dinosaur Project in China, 1987- 1990. Canadian Journal of primitive land from the Upper Cretaceous of Mongolia. Earth Sciences, 30: 1997 -2001. Palaeontologica Polonica, 27: 85 -92. Dong, Z.M., and Currie, P.J. 19%. Protoceratopsian embryos Mlynarski, M. 1976. Testudines. In Handbuch der Palaoherpetologie, from Inner Mongolia, People's Republic of China. Canadian part 7. Edited by 0. Kuhn. Gustav Fischer Verlag, Stuttgart, Journal of Earth Sciences, 30: 2248-2254. pp. 1-130. Eberth, D .A. 1993. Depositional environments and facies transitions Peng, J.-H., and Brinkman, D.B. 1994. New material of Xinjiang- of dinosaur-bearing Upper Cretaceous redbeds at Bayan Mandahu chelys (Reptilia: Testudines) from the Late Jurassic Qigu (Inner Mongolia, People's Republic of China). Canadian Formation (Shishugou Group) of the Pingfengshan locality, Journal of Earth Sciences, 30: 2196-2213. Junggar Basin, Xinjiang. Canadian Journal of Earth Sciences, Gilmore, C.W. 1931. Fossil turtles of Mongolia. Bulletin of the 30: 2013-2026. American Museum of Natural History, 59: 213 -257. Rieppel, 0. 1980. The skull of the Upper Jurassic cryptodire turtle Jerzykiewicz, T., and Russell, D. A. 1991. Late Mesozoic stratig- Thalassemys, with a reconsideration of the chelonian braincase. raphy and vertebrates of the Gobi Basin. Cretaceous Research, Palaeontographica, Abteilung A, 171: 105 - 140. 12: 345-377. Sukhanov, V.B., and Narmandakh, P. 1977. The shell and limbs Jerzykiewicz, T., Currie, P.J., Eberth, D.A., Johnston, P.A., of Basilemys orientalis (Chelonia, Dermatemydidae). A contri- Koster, E.H., and Zheng, J.-J. 1993. Djadokhta Formation bution to the morphology and evolution of the genus. Fauna, correlative strata in Chinese Inner Mongolia: an overview of the flora i biostratgrafya Mezozoya i Kainozoya Mongolii. Trudy stratigraphy, sedimentary geology, and paleontology and Sovmestnaya Sovetsko-Mongol'skaya Nauchno-Issledovatel'skaya comparisons with the type locality in the pre-Altai Gobi. Geologicheskaya Ekspeditsiya, 4: 57-79. (In Russian.) Canadian Journal of Earth Sciences, 30: 2180-2195. For personal use only. Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by "National Science Library, Chinese Academy of Sciences" on 04/05/16