Zangerlia Ukhaachelys, New Species, a Nanhsiungchelyid Turtle from the Late Cretaceous of Ukhaa Tolgod, Mongolia

Home , Adocidae, Adocus, Basilemys, Compsemys, Nanhsiungchelyidae

PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024 Number 3481, 19 pp., 6 ®gures July 25, 2005

Zangerlia ukhaachelys, New Species, a Nanhsiungchelyid Turtle from the Late Cretaceous of Ukhaa Tolgod, Mongolia

WALTER G. JOYCE1 AND MARK A. NORELL2

ABSTRACT The Late Cretaceous continental deposits of Ukhaa Tolgod, Mongolia, have yielded remains of a new NANHSIUNGCHELYID turtle, Zangerlia ukhaachelys, n.sp. This taxon is based on a single individual that consists of a partial cranium, representatives of all peripherals, an almost complete plastron, and limb fragments. Zangerlia ukhaachelys is diagnosed as a new taxon by the presence of an anteromedial process of the hyoplastron that reduces the typical contact of the entoplastron with the epiplastron. Phylogenetic analysis ®rmly places Zangerlia ukhaachelys as sister to Zangerlia testudinimorpha and Zangerlia neimongolensis within NANHSI- UNGCHELYIDAE and con®rms the close phylogenetic relationships between Nanhsiungchelys wuchingensis and Anomalochelys angulata and among all North American representatives of Basilemys. In addition, there is modest support that all Asian representatives of NANHSI- UNGCHELYIDAE form a monophyletic clade, which is primarily diagnosed by a deep, triangular nuchal notch. From a biogeographic standpoint, it is evident that the Late Cretaceous faunas of Asia and North America are closely related; however, phylogenetic considerations dem- onstrate that faunal exchange was limited for the NANHSIUNGCHELYIDAE.

INTRODUCTION the Late Cretaceous of North America. Asian Central Asian continental deposits have faunas are characterized by representatives of yielded a diverse fauna of Late Cretaceous the ADOCIDAE,CARETTOCHELYIDAE, Lindhol- turtles that are closely related to those from memydidae, NANHSIUNGCHELYIDAE, Macro-

1 Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511 (walter. [email protected]). 2 Division of Paleontology, American Museum of Natural History ([email protected]).

baenidae, Mongolochelyidae, and TRIONY- phylogenetically de®ned clade names as pre- CHIDAE and contain both aquatic and terres- sented by Joyce et al. (2004) and herein (see trial forms (Sukhanov, 2000). Together with below). These names are distinguished from faunas from the Late Cretaceous of North traditional rank-based taxonomic names by America, these groups are of special impor- the small capitals type style throughout the tance to the systematics of turtles, as they text. may have given rise to many living cryptodiran groups. As basal relationships of crown MATERIALS CRYPTODIRA are still under debate, a better Several turtle specimens were used for understanding of the morphology of these comparative purposes and were integrated turtles may be crucial to resolving patterns into a phylogenetic analysis. These include: of CRYPTODIRE evolution. Adocus (orig. Emys) beatus (Leidy, 1865), as Late Cretaceous deposits at Ukhaa Tolgod described by Marsh (1890), Hay (1908), have produced thousands of vertebrate fossils White (1972), and personal observation (Dashzeveg et al., 1995), many of which (WGJ) of YPM 782, holotype of A. puncta- have been exquisitely preserved. Interesting- tus Marsh, 1890; Adocus sp., as described by ly, despite the great abundance of fossil Meylan and Gaffney (1989); Zangerlia tes- mammals, lizards, and dinosaurs, only a few tudinimorpha Mlynarski, 1972, as described turtles have been discovered to date. During by Mlynarski (1972); Zangerlia neimongo- the 1993 joint expedition of the Mongolian lensis Brinkman and Peng, 1996, as de- Academy of Sciences and the American Mu- scribed by Brinkman and Peng (1996) and seum of Natural History, a partial skeleton of personal observation (WGJ) of casts of IVPP a fossil turtle was uncovered from this lo- 020788±7, holotype of Z. neimongolensis; cality and preliminarily identi®ed as Basile- ``Basilemys'' orientalis Sukhanov and Nar- mys? (Dashzeveg et al., 1995). The purpose mandakh, 1977, as described by Sukhanov of this paper is to formally describe this and Narmandakh (1977) and coded by Hir- specimen as a new species of NANHSI- ayama et al. (2001); Anomalochelys angulata UNGCHELYIDAE and to explore phylogenetic Hirayama et al., 2001, as described by Hir- relationships within this clade of turtles. ayama et al. (2001); Nanhsiungchelys wuch- INSTITUTIONAL ABBREVIATIONS: IGM, In- ingensis Yeh, 1966, as described by Yeh stitute of Geology, Mongolia, Ulannbaatar (1966) and coded by Hirayama et al. (2001); Mongolia; IVPP, Institute of Vertebrate Pa- Basilemys (orig. Compsemys) variolosa leontology and Paleoanthropology, Beijing, Cope, 1876, carapace and plastron as de- People's Republic of China; YPM, Yale Pea- scribed and depicted by Langston (1956), body Museum, New Haven, CT. cranial and other nonshell characters as TERMINOLOGY: Anatomical terms of the scored by Hirayama et al. (2001); Basilemys cranium follow those summarized by Gaff- nobilis Hay, 1911, carapace and plastron as ney (1972) and those of the shell as recom- described and depicted by Langston (1956), mended by Zangerl (1969). However, the an- postcranial characters as scored by Hirayama terior two pairs of plastral scutes are termed et al. (2001); Basilemys sinuosa Riggs, 1906, ``gulars'' and ``extragulars'' to clearly distin- as described and depicted by Riggs (1906); guish them from the similarly situated, but Basilemys praeclara Hay, 1911, as described ostensibly nonhomologous, ``gulars'' and by Brinkman and Nicholls (1993); and Bas- ``intergulars'' of other turtles (Hutchison and ilemys sp., as described by Brinkman (1998). Bramble, 1981). Because the generic assign- ment of most NANHSIUNGCHELYIDS has varied METHODS substantially over the last two decades (e.g., Sukhanov and Narmandakh, 1977; Meylan The phylogenetic review of NANHSI- and Gaffney, 1989; Brinkman and Peng, UNGCHELYIDAE developed by Hirayama et al. 1996; Sukhanov, 2000; Hirayama et al., (2001) is the basis for this analysis, but the 2001), we use the assignments used by Hir- character matrix was subjected to minor ayama et al. (2001). Wherever possible, taxa changes. In particular, additional states were that are more inclusive are referred to with added to characters 18 and 24 (17 and 20 of 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 3

Hirayama et al., 2001), and characters 25, 26, marily due to signi®cant amounts of missing and 32 of Hirayama et al. (2001) were split data to the cranial region of most currently into separate characters (characters 26±29, known NANHSIUNGCHELYIDS. The data matrix 33, and 35) to encompass greater morpho- was assembled using McClade 3.08 (Maddi- logical variation. In contrast, character 16 is son and Maddison, 1999) and analyzed using a hybrid of characters 22 and 24 of Hirayama PAUP 4.0b10 (Swofford, 2002). Four phylo- et al. (2001), as the original character de®ni- genetic analyses were performed that differ in tions are redundant. A list of modi®ed char- their inclusion of the geographical character acter de®nitions is provided in appendix 1. and in the ordering of the four multistate char- Four new characters were added to the acters. Characters were considered reversible analysis (6, 17, 35, 40) and two were re- and of equal weight in all analyses. Under moved from the analysis. Character 8 of Hir- parsimony settings, branches were set to be ayama et al. (2001) refers to the amount of collapsed if their minimum length was zero. ossi®cation that the canal for the carotid ar- Bootstrap values were calculated using PAUP tery exhibits posterior to the junction with 4.0b10. See appendices 1 and 2 for a com- the palatine artery. Because of the poor pres- plete list of characters used and the taxonomic ervation of the NANHSIUNGCHELYID skull ma- distribution of character states. terial, we are not con®dent in scoring the presence or absence of this character from PHYLOGENETIC NOMENCLATURE the literature. Omission of this character for- NANHSIUNGCHELYIDAE, Converted tunately has no impact on the analysis, be- Clade Name cause the derived condition is purported as present only in Nanhsiungchelys wuchingen- DEFINITION:``NANHSIUNGCHELYIDAE'' re- sis (Hirayama et al., 2001). fers to the most inclusive clade containing According to character 16 of Hirayama et Nanhsiungchelys wuchingensis Yeh, 1966, al. (2001), a unique sculpturing of the shell but not Adocus (orig. Emys) beatus (Leidy, unites all members of the NANHSIUNGCHELYI- 1865) or any species of Recent turtle. DAE into a monophyletic group. Indeed, the DISCUSSION: The name Nanhsiungchelyi- shells of all ingroup turtles are characterized dae was originally coined by Yeh (1966), but by sculpturing, but the morphology of these he only referred Nanhsiungchelys wuchin- sculptures ranges from ®ne grooves and gensis to its content. It is current taxonomic crenulations (e.g., Anomalochelys angulata) practice to assign all turtles to the taxon to uneven pits and pock-marks (e.g., Basile- Nanhsiungchelyidae that are hypothesized to mys variolosa, Zangerlia testudinimorpha), be more closely related to Nanhsiungchelys making it dif®cult to objectively compare or wuchingensis than any species of Adocus homologize them. Given that the character is (e.g., Brinkman and Peng, 1996; Sukhanov, uninformative as currently presented, and 2000; Hirayama et al., 2001). We ®x this re- that the outgroup Adocus sp. is also charac- lationship by tying the name ``NANHSI- terized by sculpturing, we omitted it. UNGCHELYIDAE'' to the most inclusive clade Finally, the codings of characters 2±5, 8, of turtles that contains Nanhsiungchelys 12, 13, 20, 21, 23, 26, and 28 of Hirayama wuchingensis but not Adocus beatus. et al. (2001) were reversed. This adjustment HYPOTHESIZED CONTENT:NANHSIUNGCHE- is purely cosmetic and was only undertaken LYIDAE is hypothesized to contain the follow- to evenly render all primitive characters dis- ing taxa: Nanhsiungchelys wuchingensis played in the outgroup Adocus sp. as ``0'' Yeh, 1966, Anomalochelys angulata Hiraya- and all derived characters as ``1'' or ``2''. ma et al., 2001, Basilemys (orig. Compse- The ®nal data matrix includes 39 osteolog- mys) variolosa (Cope, 1876), B. nobilis Hay, ical characters and one geographical character 1911, B. sinuosa Riggs, 1906, B. praeclara with 44 derived character states for 10 rep- Hay, 1911, ``Basilemys'' orientalis Sukhanov resentatives of NANHSIUNGCHELYIDAE and the and Narmandakh, 1977, Zangerlia testudi- outgroup Adocus sp. Including geography, nimorpha Mlynarski, 1972, Z. neimongolen- this matrix only includes 18 informative char- sis Brinkman and Peng, 1996, and Z. ukhaa- acters with 22 derived character states, pri- chelys, n.sp. 4 AMERICAN MUSEUM NOVITATES NO. 3481

ADOCIDAE, Converted Clade Name agnosed by a single autapomorphy, the presence of an anteromedial process of the hy- DEFINITION:`ÀDOCIDAE'' refers to the oplastron that limits contact between the en- most inclusive clade containing Adocus toplastron and epiplastron. In addition, Zan- (orig. Emys) beatus (Leidy, 1865) but not gerlia ukhaachelys is diagnosed by the Nanhsiungchelys wuchingensis Yeh, 1966 or following list of synapomorphies and sym- any species of Recent turtle. plesiomorphies: cranium with enlarged nasal DISCUSSION: The name Adocidae was orig- cavity; wide ®ssura ethmoidalis; well-devel- inally coined by Cope (1870), but he only oped upper temporal emargination; frontals referred all species then thought to be in- do not contribute to orbit and produce de- cluded in the genus Adocus. In the last 20 scending processes that almost surround sul- years, the referred content of Adocidae has cus olfactorius ventrally; lingual ridges ab- varied markedly (e.g., Mlynarski, 1976; sent; antorbital groove present along anter- Gaffney and Meylan, 1988; Sukhanov, oventral rim of orbit; shell covered with deep 2000), but all of these usages overlap in the pock-marks, deep nuchal notch formed by exclusion of Nanhsiungchelys wuchingensis. small and trapezoid nuchal and ®rst periph- Consequently, we tie the name `ÀDOCIDAE'' eral; vertebral and pleural scutes do not over- to the most inclusive clade of turtles that lap onto peripherals; entoplastron dissected contains Adocus beatus but not Nanhsi- by humero-pectoral sulcus; four pairs of in- ungchelys wuchingensis. framarginals present which fully separate HYPOTHESIZED CONTENT: Estimating the marginals from plastral scutes; marginal VI hypothesized content of ADOCIDAE is cur- not expanded ventromedially; pectoral does rently highly speculative because a phylo- not contribute to axillary notch; midline plas- genetic analysis is not available. Likely can- tral sulci straight. didates, however, include some North Amer- ican taxa placed in the North American ge- DESCRIPTION AND COMPARISON OF IGM 90/1 nus Adocus (see Hay, 1908) and numerous taxa placed in the Asian genera Adocoides PRESERVATION and Ferganemys (see Sukhanov, 2000). Unlike many other fossils from the locality of Ukhaa Tolgod, IGM 90/1 is only moder- SYSTEMATIC PALEONTOLOGY ately well preserved and shows signs of pre- TESTUDINES BATSCH, 1788 or postdepositional decay due to scavenging and/or postburial insect activity. Most limb CRYPTODIRA COPE, 1868 elements are absent, and only fragmentary NANHSIUNGCHELYIDAE YEH, 1966 remains of the girdles were found within the Zangerlia ukhaachelys, new species shell. No traces of vertebral column elements, including the neural elements of the HOLOTYPE: IGM 90/1 (®gs. 1±4), incom- carapace, are present. Despite the lack of plete skeleton consisting of partial cranium, these elements, parts of the skull remain in- peripherals, plastron, and fragmentary other tact and display details in morphology never remains of the postcranium. seen before in a nanhsiungchelyid turtle. The TYPE LOCALITY: Ukhaa Tolgod, just south skull was found within the carapace just of Xanadu, Omongov Aimag, Mongolia. The above the entoplastron. This position, how- Ukhaa Tolgod beds have been considered to ever, is not considered positive evidence for be roughly equivalent to Djadoktha (Loope full neck retraction in NANHSIUNGCHELYIDAE, et al., 1998; Dashzeveg et al., 1995). Dja- but may be coincidental, because the cranium doktha beds elsewhere in Mongolia are con- is not in articulation with the neck and may sidered to be Late Campanian (Lillegraven have been moved before ®nal deposition. and McKenna, 1986; Gao and Norell, 2000). The shell is incompletely preserved and ETYMOLOGY: `Ùkhaa'', in reference to the many areas that are useful in diagnosing fossil locality Ukhaa Tolgod, Mongolia, and NANHSIUNGCHELYID species are missing. Only ``chelys'', Greek for turtle. the anterior and lateral peripherals remain of DIAGNOSIS: Zangerlia ukhaachelys is di- the carapace, thus obscuring the morphology 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 5

Fig. 1. Zangerlia ukhaachelys. IGM 90/1, holotype, Upper Cretaceous of Mongolia. Photographs were manipulated digitally to enhance sutures. A, Oblique dorsal view of mandible; B, dorsal view of mandible; C, dorsal view of cranium; D, ventral view of cranium. Abbreviations: desc proc, descending process of frontal; ex, exoccipital; fr, frontal; mx, maxilla; op, opisthotic; pa, parietal; pf, prefrontal; pm, premaxilla; po, postorbital; pro, prootic; qu, quadrate; rec lab op, recessus labyrinthicus opistho- ticus; rec lab pro, recessus labyrinthicus prooticus; so, supraoccipital; vo, vomer; ?, bone of uncertain homology. of most carapacial scutes and the nuchal and PREFRONTAL: The prefrontal of IGM 90/1 pygal region. The plastron is more complete, consists of a dorsal plate, which forms the but signi®cant parts of the anterior lobe and roof of a broad fossa nasalis, and a vertical the bridges are missing or they are heavily plate, which forms signi®cant portions of the weathered. The larvae of large scavenging anterior orbit wall. In dorsal view, the pre- beetles likely produced the holes seen in the frontal has a posteromedial contact with the plastron (®gs. 1±4). frontal, a medial contact with its counterpart, and a small posterolateral contact with the CRANIUM AND MANDIBLE postorbital, thus excluding the frontal from The most interesting aspect of IGM 90/1 contributing to the orbital rim. The anterior is its uncrushed, partial cranium, which is the rims of both prefrontals are weathered away, best preserved of any nanhsiungchelyid and making it unclear if nasals were present an- clearly exhibits all cranial sutures (®gs. 1, 2). teriorly. In lateral view, the vertical plate of 6 AMERICAN MUSEUM NOVITATES NO. 3481

Fig. 2. Zangerlia ukhaachelys, cranium of IGM 90/1, holotype, Upper Cretaceous of Mongolia. Photographs were manipulated digitally to enhance sutures. A, Left lateral view; B, right lateral view; C, frontal view; D, caudal view. See ®gure 1 for abbreviations. 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 7 the prefrontal meets the ascending process of In contrast, the fronts of Adocus sp. and N. the maxilla along a short interdigitated con- wuchingensis clearly do so. tact to form the lateral wall of the fossa na- PARIETAL: The parietals are partially pre- salis. An additional, elongate contact be- served in IGM 90/1. Due to the great ex- tween these bones exists along the anterov- panse of the prefrontal and frontal, this bone entral rim of the orbit. Although the distal contributes very little to the dorsal surface of ends of the ascending process of the prefron- the skull between the upper temporal emar- tals are weathered, the left one is better pre- ginations. It contacts the frontal anteriorly served and shows the presence of a moder- along an interdigitated transverse suture, ately sized foramen orbito-nasale. The ®ssura meets its counterpart medially, and sends a ethmoidalis and the sulcus olfactorius are ap- small process anterolaterally along the rim of parent and are notably wide. the upper temporal emargination to contact a The prefrontal of IGM 90/1 closely resem- similar postorbital process. No contacts are bles that of Zangerlia neimongolensis. It also present with the jugal, quadratojugal, or resembles the prefrontals of Adocus sp., but squamosal because of the presence of a well- differs by having a contact with the postor- developed upper temporal emargination. bital and by covering a much larger propor- Posteriorly, the parietal narrows to form the tion of the dorsal roo®ng of the skull be- anterior part of the crista, but the posterior tween the orbits. The ®ssura ethmoidalis tip that overlies the supraoccipital is missing. greatly resembles that of the TESTUDINIDAE in The ventral portion of the parietal is less being wide and not keyhole-shaped. complete, but it appears to have formed much of the dorsal aspect of the lateral brain- FRONTAL: In dorsal view, the frontal of IGM 90/1 is ¯at and subtriangular. It meets case wall, as in all crown group turtles. The the prefrontal anterolaterally, the postorbital parietal of IGM 90/1 appears to have con- laterally, the other frontal medially, and the tributed a little to a distinctly protruding pro- parietal along an interdigitated suture poste- cessus trochlearis oticum. The parietal of IGM 90/1 resembles that riorly. It is a large element forming much of of Adocus sp., but it differs by contributing the skull roof, but it does not contribute to less to the skull roof and by having a small the orbital rim. The frontal generally has a contact with the postorbital. The contacts of smooth surface, but a faint sulcus crosses it the parietal are unknown for Z. neimongolen- in an arch. The morphology of the frontal is sis. The parietal of N. wuchingensis differs more complex in ventral view. Between the markedly by roo®ng much of the upper tem- parietal and the prefrontal, it forms a signif- poral fossa and by having contact with the icant portion of the sulcus olfactorius. From squamosal. the rim of the sulcus, tapered processes as- POSTORBITAL: The postorbital is a small el- cend from both frontals that almost meet me- ement that forms most of the slim postorbital dially, practically rendering the sulcus olfac- bar. It contacts the prefrontal anteromedially torius a canal. Transverse to the sulcus olfac- and the parietal posteromedially, thus exclud- torius, the prefrontal additionally forms a ing the frontal from the orbit and the upper small ridge that runs parallel to its border temporal emargination. It also contacts an el- with the parietal and forms the posterodorsal ement laterally, but the condition of the skull limit of the orbit. does not permit the identi®cation of this bone The skull materials of Z. neimongolensis as the jugal or quadratojugal. and N. wuchingensis are not prepared enough PREMAXILLA: The premaxilla of IGM 90/1 to assess the presence of a descending frontal is a small element that meets the maxilla lat- process in these taxa. These processes are not erally, its counterpart medially, and the vo- known in Adocus sp. Among living turtles, mer posteriorly and that forms the ventral descending frontal processes are known from rim of the external nares. Together with the a number of TESTUDINOID turtles, especially maxilla, it forms a distinct, evenly serrated terrestrial forms of the TESTUDINIDAE. The labial ridge. In ventral view, the premaxillae frontals of Z. neimongolensis do not contrib- form the anterior portion of the narrow trit- ute to the orbital rim, as seen in IGM 90/1. urating surface. The position of the foramen 8 AMERICAN MUSEUM NOVITATES NO. 3481 praepalatinum is unclear. No signi®cant dif- served, but the entire paroccipital process is ferences are apparent from the premaxilla of missing. Together with the prootic, it forms Adocus sp. or Z. neimongolensis. Although a parasagittal groove within the upper tem- the premaxilla was neither explicitly men- poral fossa. In ventral view, a number of in- tioned nor depicted by Yeh (1966) for N. ternal structures are apparent, such as the re- wuchingensis, it must have deviated from the cessus labyrinthicus prooticus and opisthoti- morphology of IGM 90/1 greatly, because cus, but the specimen is too fragile to allow the entire nasal region of this taxon protrudes further preparation of this area. A small frag- to form a tubular snout. ment of the exoccipital remains posterior to MAXILLA: Both maxillae of IGM 90/1 are the opisthotic, but only the hypoglossal nerve present, but only the right one is well pre- foramina are apparent. served. This bone contacts the premaxilla an- DENTARY: Only the anterior portions of teriorly, the prefrontal dorsally and along the both mandibular rami remain in IGM 90/1. anteroventral rim of the orbit, and the vomer The dentary is a narrow element that meets along a small suture posteromedially. It is its counterpart along a narrow suture medi- likely that it contacts the jugal, pterygoid, ally. The labial ridge is very low in what and palatine; however, this cannot be directly remains, and a modest triturating surface is observed in this specimen. The maxilla present that overhangs the medial interden- forms the vast majority of the coarsely ser- tary suture. rated labial ridge in ventral view. A lingual ridge is absent, and the triturating surface is rather narrow and only slightly sculpted. In CARAPACE lateral view, an antorbital groove is apparent Only some peripherals remain of the car- that lies parallel to the anteroventral rim of apace. On the left side, peripherals I±V are the orbit. preserved in articulation. The most anterior The maxilla of IGM 90/1 generally resem- peripheral is identi®able as peripheral I, be- bles that of Adocus sp. and Z. neimongolen- cause it forms the apex of a deep nuchal sis, but Adocus sp. is lacking the antorbital groove. The shape of the maxilla of N. wuch- notch. Such nuchal notches are typical of ingensis has little resemblance to that of IGM NANHSIUNGCHELYIDAE and are always formed 90/1. by the nuchal and the ®rst peripheral. Al- though the nuchal is missing in IGM 90/1, it VOMER: Only the anterior portion of the vomer is preserved. As in most CRYPTODIRES, can be inferred to have been small, similar it contacts the maxilla anterolaterally and the to that found in ``Basilemys'' orientalis. Pe- premaxilla anteromedially and separates the ripheral III, IV, and V loosely articulate with internal narial openings. The position of the the hyoplastron. On the right side, the anterior praepalatine foramen is not clear. No discrete element can be identi®ed as peripheral III, differences are apparent with Adocus sp. and based on its articulation with the hyoplastron, Z. neimongolensis. followed by peripherals IV, V, and VII±X. BRAINCASE ELEMENTS: Fragments of the Peripheral I is a pentagonal element. Its left supraoccipital, prootic, opisthotic, exoc- anterolateral side forms the carapace margin, cipital, and quadrate are preserved in IGM and the anteromedial side forms the deep nu- 90/1. Only the anterior portion of the supra- chal notch. Peripheral II is rectangular and occipital remains to form the lateral brain- almost twice as wide as long. Peripherals II± case wall and the lateral rim of the foramen IX are bridge peripherals. The anterior three magnum. It is predominantly in contact with bridge elements are in contact with the hy- the parietal anteriorly and medially and with oplastron, and the posterior four are in con- the opisthotic laterally. The processus troch- tact with the hypoplastron. The angle that is learis oticum is not distinct and appears to formed between the dorsal and ventral plates be predominantly formed by the parietal and of these peripherals is approximately 90Њ.In quadrate. The prootic contributed to this life, the actual angle of the carapace, how- structure with a minor sliver only. The an- ever, was probably only 50Њ. All elements teromedial portions of the opisthotic are pre- have clear traces of marginal scutes. The 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 9 pleural and vertebral scutes did not reach the suture at its regular position on the right side, peripherals. con®rming the ®delity of the morphology depicted on the left. Detached remains of the PLASTRON epiplastra indicate that the anterior rim of the plastron was rounded and that the gular scute The plastron of IGM 90/1 is well pre- extended onto a thickened dorsal lip. served, although signi®cant portions of the BRIDGE REGION: The bridge of IGM 90/1 anterior plastral lobe and the bridges are is formed by the hyoplastron and hypoplas- missing (®gs. 3, 4). An elongate central fon- tron. Mesoplastra are absent. Anterior and tanelle and two small, semilunate lateral fon- posterior plastral buttresses are present but tanelles are formed by the hyo- and hypo- are only poorly developed, as in all NANHSI- plastra. Central fontanelles are also known UNGCHELYID turtles. The anterior plastral but- from Zangerlia neimongolensis. Most sulci tress reaches to contact the third peripheral, can be clearly traced, but due to the poor and the posterior buttress just barely appears preservation of the anterior bony elements, to contact the ninth peripheral. Distally, the there is no evidence of gulars and extragu- buttresses ¯are into numerous ®ngers, which lars. All plastral elements are ornamented established a loose, sutural connection be- with irregular grooves and pits, a feature tween the carapace and the plastron. The ax- characteristic of many TRIONYCHOIDS. All illary notch is positioned just slightly farther bony sutures can be traced easily, because anteriorly than the posterior end of the en- the bones only contact each other bluntly, toplastron and the inguinal notch just slightly thus allowing the elements to separate after anterior to the hypo/xiphiplastral suture. death. Given the signi®cantly smaller size of POSTERIOR PLASTRAL ELEMENTS: The pos- IGM 90/1 relative to other members of the terior plastral lobe is formed predominantly NANHSIUNGCHELYIDAE, this weak develop- by the xiphiplastron. This is typical for ment of the bony contacts together with the NANHSIUNGCHELYIDAE. Like most turtles, the lateral fontanelles may represent juvenile suture between the hypoplastron and xiphi- features. plastron is generally straight but is Z-shaped ANTERIOR PLASTRAL ELEMENTS: Although near the lateral rim. much of the anterior plastron lobe is missing PLASTRAL SCUTES: No clear traces of the or detached, it is apparent that this lobe was gulars and extragulars can be found. This is rather well developed, probably reaching far- unfortunate, as many diagnostic features of ther anteriorly than the carapace rim. This NANHSIUNGCHELYIDAE can be found in this re- feature is typical for NANHSIUNGCHELYID tur- gion. Similar to Zangerlia neimongolensis, tles. The entoplastron is a large, diamond- the humero-pectoral sulcus clearly intersects shaped element that is fully surrounded by the entoplastron medially, but it is unclear the epiplastra anteriorly and thus is excluded where this sulcus terminates laterally. As in from the plastral rim. A unique characteristic all NANHSIUNGCHELYID turtles, the pectoral in- of IGM 90/1 is the arrangement of contacts creases in length medially, but its midline between the entoplastron, epiplastron, and sulcus appears to be straight, unlike in Bas- hyoplastron. In all crown group turtles with ilemys spp. The lateral contacts of the pec- a well-ossi®ed plastron, including Adocus toral are unclear, but the pectoral appears to and all representative of NANHSIUNGCHELYI- widen slightly to contact the ®rst two infra- DAE, the entoplastron is a diamond-shaped el- marginals. The pectoral does not contribute ement that only contacts the epiplastron to the anterior plastral rim. The abdominal is along its anterolateral side. In IGM 90/1, the a subrectangular element, with the exception hyoplastron sends a triangular process an- of a small posterolateral process that contrib- terolaterally that separates the epiplastron utes to the rim of the inguinal notch and hin- from the entoplastron, thus limiting the con- ders contact between the femoral and the tact that usually exists between these two el- posterior inframarginal. The anal is a trian- ements. Although this morphology is only gular element and its medial contact is clearly seen on the left side and may be con- straight, as in Z. testudinimorpha. sidered an anomaly, there is no trace of a IGM 90/1 has a complete row of four in- 10 AMERICAN MUSEUM NOVITATES NO. 3481

Fig. 3. Zangerlia ukhaachelys, IGM 90/1, holotype, Upper Cretaceous of Mongolia. Ventral view of plastron. framarginals. The anterior inframarginal is ally and the abdominal posteromedially. The the least well preserved. Only its posterior third inframarginal is an elongate, rectangu- sulcus with the second inframarginal is clear- lar element and spans the hyo-/hypoplastral ly visible. The second inframarginal is a pen- suture. It is subequal in length with the other tagonal element that has a straight lateral inframarginals. The posterior inframarginal contact with the marginals, a straight anterior is less visible, but it appears to become sig- contact with the ®rst inframarginal, and a ni®cantly wider posteriorly. The marginals straight posterior contact with the third infra- clearly overlap onto the plastron, but no in- marginal. It meets the pectoral anteromedi- termarginal sulci are apparent on the ventral 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 11

Fig. 4. Zangerlia ukhaachelys, IGM 90/1, holotype, Upper Cretaceous of Mongolia. Ventral view of plastron. Abbreviations: AB, abdominal scute; AN, anal scute; ent, entoplastron; epi, epiplastron; FE, femoral scute; HU, humeral scute; hyo, hyoplastron; hyp, hypoplastron; IM, inframarginal scute; PE, pectoral scute; per, peripheral; xi, xiphiplastron.

side. A row of four equally sized inframar- Zangerlia spp. and Basilemys spp. are re- ginals is unique among NANHSIUNGCHELYIDS. duced both in number and in size. ``Basilemys'' orientalis also has a complete row of inframarginals, but the third infra- POSTCRANIAL ELEMENTS marginal is at least three times longer than Few postcranial elements were found as- the other elements. The inframarginals of sociated with IGM 90/1. Additional elements 12 AMERICAN MUSEUM NOVITATES NO. 3481 may be hidden in the remaining matrix; how- the pleural and vertebral scutes onto the pe- ever, further preparation was not undertaken ripherals and the pygal. Although the nuchal to avoid destabilizing the plastron. is not present in IGM 90/1, it can be clearly SCAPULA: The scapular process is exposed inferred not to have been a large V-shaped in dorsal view, but the remaining parts of the element as seen in Anomalochelys angulata scapula are still covered by sediments. The or Nanhsiungchelys wuchingensis, because scapular process is ¯attened in cross section, the adjacent ®rst peripheral closely ap- its shaft is striated, and it is curved. From proached the midline not allowing room for what can be seen, this element greatly resem- a large nuchal. IGM 90/1 differs from ``Bas- bles the scapula of Zangerlia neimongolen- ilemys'' orientalis by possessing subequally sis. sized inframarginals and by lacking a sinu- SACRAL RIBS: Two sacral ribs are pre- ous interanal sulcus and a ventromedially ex- served just posterior to the plastron (®gs. 3, panded sixth marginal. Within Zangerlia, 4). Like the sacral ribs of most CRYPTODIRES, IGM 90/1 differs from Z. neimongolensis and these elements are narrow distally for artic- Z. testudinimorpha by its complete row of ulation with the ilium, but they expand prox- four subequally sized inframarginals. Most imally for articulation with the sacral verte- importantly, IGM 90/1 can be differentiated brae. Unlike those of other CRYPTODIRES, the from all other representatives of Zangerlia sacral ribs of Zangerlia ukhaachelys are ap- and all turtles in general by the development proximately ®ve times wider proximally than of an anteromedial process of the hyoplas- distally, and the proximal end is ¯attened, tron that hinders a full contact between the not cylindrical. Comparative material is not anterolateral side of the entoplastron with the available from other NANHSIUNGCHELYIDS. epiplastron. These differences, especially the ILIUM AND TIBIA: A single, partially arrangement of bones in the anterior plastral crushed element is present in close associa- lobe, clearly diagnose IGM 90/1 as a new tion with the sacral ribs that is tentatively species, which we name Zangerlia ukhaa- interpreted as the ilium (®gs. 3, 4). This iden- chelys in reference to the type locality, ti®cation is supported by a slight distal ex- Ukhaa Tolgod, Mongolia. pansion to the bone and the presence of three facets proximally that may correspond to the PHYLOGENETIC RELATIONSHIPS articular sites with the pubis and ischium and the acetabulum. Adjacent to the left inguinal The assemblage of turtles currently hy- buttress another bone is preserved which ap- pothesized to belong to NANHSIUNGCHELYI- pears to be a tibia. Both elements are unusu- DAE (i.e., Basilemys variolosa,``Basilemys'' ally short relative to the length of the cara- orientalis, Nanhsiungchelys wuchingensis, pace, however, making this identi®cation Zangerlia testudinimorpha) was formally somewhat uncertain. Additional material of recognized as a phylogenetic unit by Suk- Zangerlia ukhaachelys will certainly help re- hanov and Narmandakh (1977), who placed veal the identity of these elements. all of these taxa into Basilemys. Subsequent- ly, most authors have agreed that these turtles DISCUSSION form a monophyletic group (e.g., Meylan and Gaffney, 1989; Brinkman and Peng, IGM 90/1 exhibits a number of character- 1996; Sukhanov, 2000; Hirayama et al., istics of the NANHSIUNGCHELYIDAE that help 2001). The phylogenetic relationships within distinguish it from all other turtles. These in- NANHSIUNGCHELYIDAE have only been scru- clude the antorbital groove of the maxilla, tinized within a cladistic framework for the the short limbs, the well-developed anterior last 15 years. Notably, Meylan and Gaffney plastral lobe, a thickened epiplastral lip, and (1989) placed NANHSIUNGCHELYIDAE as the the absence of a pectoral contribution to the sister to Peltochelys and TRIONYCHIA within axillary rim. Unlike all representatives of the the TRIONYCHOIDEA, but they did not resolve North America Basilemys, IGM 90/1 is char- internal relationships. Using the ®rst species- acterized by a full set of four inframarginals level cladistic analysis, Brinkman and Nich- and the complete absence of an overlap of olls (1993) demonstrated that Zangerlia tes- 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 13

Nanhsiungchelys wuchingensis and ``Basile- mys'' orientalis to represent the most basal divergence, being the sister group to all remaining taxa (®g. 5). The recent analysis of Hirayama et al. (2001) is somewhat inter- mediate relative to the previous two by con- sidering Zangerlia to be paraphyletic and by placing Zangerlia testudinimorpha basal to all other turtles (as suggested by Brinkman and Nicholls, 1993) and ``Zangerlia'' neimongolensis as sister to Basilemys (as suggested by Brinkman and Peng, 1996; ®g. 5). In this study, four analyses were performed that differ in their inclusion of the geographical character and the ordering of the four multistate characters. The resulting four strict consensus trees are given in ®gure 6. Consistency indices range from 0.84 to 0.86 or 0.72 to 0.76 after removal of uninformative characters. All four analyses support a clade comprised of Zangerlia ukhaachelys, Z. testudinimorpha, and Z. neimongolensis, a clade comprised of Nanhsiungchelys wuchingensis and Anomalochelys angulata, and a clade that includes all herein mentioned species of North American Basilemys. Bootstrap values provide good support for the clade comprised of Nanhsiungchelys wuchingensis and An- omalochelys angulata, and modest support for the clades comprised of all representatives of Zangerlia and North American Bas- ilemys, respectively. Unlike the results of Hirayama et al. (2001), this analysis supports the monophyly of Zangerlia, regardless of the inclusion of geography or the ordering of the multistate characters. If Zangerlia ukhaachelys is omitted and the paraphyly of Zangerlia forced as seen in Hirayama et al. (2001), two more steps are required in the trees that exclude geography or three in those that include ge- Fig. 5. Previously published phylogenetic hy- ography. The most parsimonious addition of potheses of NANHSIUNGCHELYIDAE. Zangerlia ukhaachelys to these forced trees (as sister to Zangerlia testudinimorpha or Zangerlia neimongolensis) requires four or tudinimorpha should be regarded as the most ®ve more steps, respectively. The strongest basal member of NANHSIUNGCHELYIDAE and evidence in favor of a monophyletic Zanger- that the Asian taxa Nanhsiungchelys wuch- lia, therefore, is not provided by the revision ingensis and ``Basilemys'' orientalis form the of the character matrix, but rather by the ad- sister group to the North American represen- dition of Zangerlia ukhaachelys to the ma- tatives of Basilemys (®g. 5). In contrast, trix. Representatives of Zangerlia are united Brinkman and Peng (1996) considered by the loss of the lingual ridge, the steep pos- 14 AMERICAN MUSEUM NOVITATES NO. 3481

Fig. 6. Phylogenetic relationships of NANHSIUNGCHELYIDAE based on this analysis. terior de¯ection of the carapace, and the a monophyletic clade of Asian NANHSI- presence of a knobby protrusion at the end UNGCHELYIDS. This topology is not seen in of the neural series. the strict consensus cladogram of the analy- As in all previous studies, our analysis in- sis that includes ordering and excludes ge- dicates the presence of a monophyletic clade ography, but it is present in one of the three of North American NANHSIUNGCHELYIDAE, most parsimonious trees that this analysis termed Basilemys. Characters that unite this provides. Characters that unite an Asian clade include the strong reduction of the in- clade of NANHSIUNGCHELYIDAE include the framarginals, which allows broad contact be- correspondence of the pleural-marginal sul- tween the marginals and plastral scutes, and cus with the costal-peripherals suture and, the broad overlap of the pleural and vertebral most notably, the formation of a deep, tri- scutes onto the peripherals and pygal. The angular nuchal notch that is unique among character that most clearly distinguishes turtles. Although we generally favor this to- these taxa from all other turtles is the broad pology, support for an Asian clade is limited. overlap of a triangular ®fth vertebral over the A paraphyletic assemblage of Asian NANHSI- tenth peripheral. UNGCHELYIDS is retrieved in two of the three In contrast to all previously published phy- most parsimonious solutions in the analysis logenies, three out of four analyses retrieve that excludes geography but includes ordered 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 15 characters, and forcing paraphyly in the other lensis type material. Donald Brinkman, Jen- analyses only results in trees one or two steps ney Hall, and James Parham are acknowl- longer. edged for their help in improving the quality The occurrence of NANHSIUNGCHELYID and of the manuscript. This work is supported by ADOCID turtles in North America and Asia the American Museum of Natural History only is evidence for the close biogeographic Division of Paleontology. Support for WGJ ties between these two landmasses during the was provided by a Yale University Graduate Late Cretaceous. The presence of a mono- Fellowship and the Yale Department of Ge- phyletic clade of North American NANHSI- ology and Geophysics. UNGCHELYIDS and an at worst paraphyletic assemblage of Asian NANHSIUNGCHELYIDS, how- REFERENCES ever, illustrates that faunal exchange between these continents was limited, at least among Batsch, A.J.G.C. 1788. Versuch einer Anleitung, these groups of turtles. zur Kenntniû und Geschichte der Thiere und Mineralien, fuÈr akademische Vorlesungen en- CONCLUSIONS tworfen, und mit den noÈthigen Abbildungen versehen. Jena: Akademische Buchhandlung. A fragmentary fossil turtle from the Late Brinkman, D. 1998. The skull and neck of the Cretaceous of Ukhaa Tolgod, Mongolia, is Cretaceous turtle Basilemys (Trionychoidea, identi®ed as a new species of NANHSIUNGCHE- Nanhsiungchelyidae), and the interrelationships LYID turtle, Zangerlia ukhaachelys. The most of the genus. Paludicola 1: 150±157. diagnostic trait that clearly distinguishes this Brinkman, D., and E. Nicholls. 1993. New spec- taxon from all other known turtles is an an- imen of Basilemys praeclara Hay and its bear- ing on the relationship of the Nanhsiungchelyi- teromedial extension of the hyoplastron that dae (Reptilia: Testudines). Journal of Paleon- hinders the usual broad anterolateral contact tology 67: 1027±1031. of the entoplastron with the epiplastron. In Brinkman, D., and J.-H. Peng. 1996. A new spe- comparison with published accounts, phylo- cies of Zangerlia (Testudines: Nanhsiungche- genetic analysis provides support for a clade lyidae) from the Upper Cretaceous redbeds and comprised of Zangerlia ukhaachelys, Z. nei- Bayan Mandahu, Inner Mongolia, and the re- mongolensis, and Z. testudinimorpha. Good lationships of the genus. Canadian Journal of support is present in favor of a clade con- Earth Sciences 33: 526±540. taining Anomalochelys angulata and Nanhsi- Cope, E.D. 1868. On the origin of genera. Pro- ungchelys wuchingensis and a clade com- ceedings of the Academy of Natural Sciences of Philadelphia 1868: 242±300. prised of all North American representatives Cope, E.D. 1870. On the Adocidae. Proceedings of Basilemys. Modest character support is of the American Philosophical Society 11: 547± also available for a clade that unites all Asian 553. NANHSIUNGCHELYIDS. Biogeographic consid- Cope, E.D. 1876. Description of some vertebrate erations indicate that the Late Cretaceous tur- remains from the Fort Union Beds of Montana. tle faunas of Asia and North America are Proceedings of the Academy of Natural Sci- rather similar, but also that the amount of ences of Philadelphia 1876: 248±261. faunal exchange was very limited, at least Dashzeveg, D., M.J. Novacek, M.A. Norell, J.M. Clark, L.M. Chiappe, A. Davidson, M.C. Mc- within NANHSIUNGCHELYIDAE. Kenna, L. Dingus, C. Swisher, and P. Altanger- el. 1995. Extraordinary preservation in a new ACKNOWLEDGMENTS vertebrate assemblage from the Late Cretaceous We thank ®eld crews of the Mongolian of Mongolia. Nature 374: 446±449. Academy of Sciences and the American Mu- Gaffney, E.S. 1972. An illustrated glossary of tur- seum of Natural History for their hard work tle skull nomenclature. American Museum Novitates 2486: 1±33. in the desert for so many years. Marilyn Fox, Gaffney, E.S. 1984. Historical analysis of theories Brian Roach, and Jane Shumsky are com- of chelonian relationship. Systematic Zoology mended for their preparation of a dif®cult 33: 283±301. specimen. Mick Ellison constructed the ®g- Gaffney, E.S., and P.A. Meylan. 1988. A phylog- ures. Special thanks to Donald Brinkman for eny of turtles. In M.J. Benton (editor), The phy- supplying casts of the Zangerlia neimongo- logeny and classi®cation of the tetrapods, vol. 16 AMERICAN MUSEUM NOVITATES NO. 3481

1: Amphibians, reptiles, birds: 157±219. Ox- Maddison, W.P., and D.R. Maddison. 1999. ford: Clarendon Press. MacClade, version 3. 08. Sunderland, MA: Sin- Gao, K.-Q., and M.A. Norell. 2000. Taxonomic auer Associates. composition and systematics of Late Creta- Marsh, O.C. 1890. Notice of some extinct Testu- ceous lizard assemblages from Ukhaa Tolgod dinata. American Journal of Science 40: 177± and adjacent localities, Mongolian Gobi Desert. 179. Bulletin of the American Museum of Natural Meylan, P.A., and E.S. Gaffney. 1989. The skel- History 249: 1±118. etal morphology of the Cretaceous cryptodiran Hay, O.P. 1908. The fossil turtles of North Amer- turtle, Adocus, and the relationships of the ica. Carnegie Institution of Washington, Publi- Trionychoidea. American Museum Novitates cation 75: 1±568. 2941: 1±60. Hay, O.P. 1911. Descriptions of eight new species Mlynarski, M. 1972. Zangerlia testudinimorpha of fossil turtles from west of the one hundredth n. gen., n. sp., a primitive land tortoise from meridian. Proceedings of the United States Na- the Upper Cretaceous of Mongolia. Palaeonto- tional Museum 38: 307±326. logia Polonica 27: 85±92. Hirayama, R., S. Kazuhiko, C. Tsutomu, K. Gen- Mlynarski, M. 1976. Handbuch der PalaÈoherpe- taro, and K. Norio. 2001. Anomalochelys an- tologie, Teil 7, Testudines. Stuttgart: Gustav Fi- gulata, an unusual land turtle of family Nanhsi- scher Verlag. ungchelyidae (superfamily Trionychoidea; or- Riggs, E.S. 1906. The carapace and plastron of der Testudines) from the Upper Cretaceous of Basilemys sinuosus, a new fossil tortoise from Hokkaido, North Japan. Russian Journal of the Laramie Beds of Montana. Field Columbian Herpetology 8: 127±138. Museum, Geological Series 2: 249±256. Hutchison, J.H., and D.M. Bramble. 1981. Ho- Sukhanov, V.B. 2000. Mesozoic turtles of middle mology of the plastral scales of the Kinoster- and central Asia. In M.J. Benton, M.A. Shish- nidae and related turtles. Herpetologica 37: 73± kin, D.M. Unwin, and E.N. Kurochkin (edi- 85. tors), The age of dinosaurs in Russia and Mon- Joyce, W.G., J.F. Parham, and J.A. Gauthier. 2004. golia: 309±367. Cambridge: Cambridge Uni- A phylogenetic nomenclature of turtles. Journal versity Press. of Paleontology 78: 989±1013. Sukhanov, V.B., and P. Narmandakh. 1977. The Langston, W. 1956. The shell of Basilemys vari- shell and limbs of Basilemys orientalis (Che- alosa (Cope). Bulletin of the National Museum lonia, Dermatemyidae): a contribution to the of Canada 142: 155±165. morphology and evolution of the genus. Fauna, Leidy, J. 1865. Cretaceous reptiles of the United ¯ora i biostratgra®ya Mezozoya i Kainozoya States. Smithsonian Contributions to Knowl- Mongolii. Sovmestnaya Sovetsko-Mongol'- edge 14: 1±135. skaya Nauchneissledovat El'skaya Geologi- Lillegraven, J.A., and M.C. McKenna. 1986. Fos- cheskaya Ekspeditsiya, Trudy 4: 57±79. sil mammals from the ``Mesaverde'' Formation Swofford, P.L. 2002. PAUP, version 4. 0b10. Sun- (Late Cretaceous, Judithian) of the Bighorn and derland, MA: Sinauer Associates. Wind River Basins, Wyoming, with de®nitions White, R.S. 1972. A recently collected specimen of Late Cretaceous North American Land of Adocus (Testudines; Dermatemydidae) from Mammal ``Ages''. American Museum Novita- New Jersey. Natulae Naturae 447: 1±10. tes 2840: 1±68. Yeh, H.-K. 1966. A new Cretaceous turtle of Linnaeus, C. 1758. Systema Naturae, vol. 1. Hol- Nanhsiung, Northern Kwangtung. Vertebrata mia: Laurentius Salvius. PalAsiatica 10: 191±200. Loope, D.B., L. Dingus, C.C. Swisher III, and C. Zangerl, R. 1969. The turtle shell. In C. Gans, Minjin. 1998. Life and death in a Cretaceous A.d.A. Bellairs, and T.S. Parsons (editors), Bi- dune ®eld, Nemegt Basin, Mongolia. Geology ology of Reptilia, vol. 1, Morphology A: 311± 26: 27±30. 339. New York: Academic Press. 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 17

APPENDIX 1

CHARACTER LIST 1. Numerous deep cranial scute sulci on cal (Hirayama et al., 2001: char. 10): (0) dermal roo®ng elements (modi®ed from opistocoelous; (1) biconvex. Hirayama et al., 2001: char. 1: (0) absent; 11. Coracoid (Hirayama et al., 2001: char. 11): (1) present. COMMENTS: Basilemys variolo- (0) ¯at and elongate; (1) ¯at, fan-shaped. sa scored according to Hirayama et al. COMMENTS: Basilemys variolosa and ``Bas- (2001). ilemys'' orientalis scored according to Hir- 2. Extensive postorbital squamosal contact ayama et al. (2001). due to the great anterior extent of the 12. Size and medial contact of thyroid fe- squamosal and the great posterior extent nestrae (Hirayama et al., 2001: char. 12): of the postorbital (modi®ed from Hiraya- (0) fenestrae large and con¯uent; (1) fe- ma et al., 2001: char. 2): (0) absent; (1) nestrae small, medial contact absent. COM- present. COMMENTS: Basilemys variolosa MENTS: Scoring of Zangerlia neimongolen- scored according to Hirayama et al. (2001). sis changed from ``1'' to ``0''. Basilemys 3. Extent of upper temporal emargination variolosa and ``Basilemys'' orientalis (Hirayama et al., 2001: char. 3): (0) fora- scored according to Hirayama et al. (2001). men stapedio-temporale fully exposed in 13. Thelial process of ilium (Hirayama et al., dorsal view; (1) foramen stapedio-tempor- 2001: char. 13): (0) present; (1) absent. COMMENTS: Basilemys variolosa,``Basile- ale concealed in dorsal view. COMMENTS: Basilemys variolosa scored according to mys'' orientalis, and Nanhsiungchelys Hirayama et al. (2001). wuchingensis scored according to Hiraya- 4. Extent of lower temporal emargination ma et al. (2001). (Hirayama et al., 2001: char. 4): (0) mod- 14. Length of manual and pedal digits (moderately developed, processus pterygoideus i®ed from Hirayama et al., 2001: char. 14): externus barely visible in lateral view; (1) (0) digits elongate, typically three phalanges per digit; (1) digits shortened, less than absent or shallow, processus pterygoideus three phalanges per digit. COMMENTS: Bas- externus concealed in lateral view. COM- ilemys variolosa, Basilemys nobilis, and MENTS: Basilemys variolosa scored accord- ``Basilemys'' orientalis scored according to ing to Hirayama et al. (2001). Hirayama et al. (2001). 5. Lingual ridges of maxilla (Hirayama et 15. Limb osteoderms (Hirayama et al., 2001: al., 2001: char. 5): (0) double; (1) single or char. 15): (0) absent; (1) present. COM- absent. COMMENTS: Basilemys variolosa MENTS: Basilemys variolosa, and Basilemys scored according to Hirayama et al. (2001). nobilis scored according to Hirayama et al. 6. Antorbital groove on the surface of the (2001). maxilla along the anteroventral rim of 16. Steep de¯ection of the postneural part of the orbit: (0) absent; (1) present. the carapace (Hirayama et al., 2001: 7. Medial contact of palatines (Hirayama et chars. 22, 24): (0) absent, posterior periph- al., 2001: char. 6): (0) absent; (1) present. erals great ¯ared; (1) present, posterior pe- COMMENTS: Nanhsiungchelys wuchingensis ripherals shortened. scored according to Hirayama et al. (2001). 17. Knobby protrusion of the carapace at 8. Incisura columella auris (Hirayama et al., the position of the ®rst suprapygal: (0) 2001: char. 7): (0) open posteriorly; (1) absent; (1) present. closed posteriorly. COMMENTS: Basilemys 18. Nuchal notch (modi®ed from Brinkman variolosa scored according to Hirayama et and Nicholls, 1993: char. 2; Hirayama et al. (2001). al., 2001: char. 17): (0) absent or shallow; 9. Size and contacts of the basisphenoid (1) present, formed by the nuchal and pe- (Hirayama et al., 2001: char. 9): (0) basi- ripheral I; (2) present, formed by nuchal sphenoid short, anteriorly only in contact only. COMMENTS: Scoring of Zangerlia tes- with pterygoid; (1) basisphenoid elongate, tudinimorpha changed from ``0'' to ``?''. anteriorly in contact with vomer or pala- 19. Shape and size of nuchal (Hirayama et al., tine. COMMENTS: Nanhsiungchelys wuchin- 2001: char. 19): (0) small and trapezoid; (1) gensis scored according to Hirayama et al. large and V-shaped. (2001). 20. Costiform process of nuchal (Hirayama et 10. Central morphology of the eighth cervi- al., 2001: char. 18): (0) absent; (1) present. 18 AMERICAN MUSEUM NOVITATES NO. 3481

COMMENTS: Scoring of Zangerlia testudi- 30. Extent of anterior plastral lobe (Hiraya- nimorpha changed from ``1'' to ``?''. ma et al., 2001: char. 36): (0) anterior lobe 21. Neurals (Hirayama et al., 2001: char. 21): covered by carapace in dorsal view; (1) an- (0) neurals VII and VIII reduced or lost; terior lobe protrudes farther anterior than (1) full set of eight neurals present. carapace. 22. Contacts of suprapygals with peripher- 31. Extragulars (modi®ed from Hirayama et als (modi®ed from Hirayama et al., 2001: al., 2001: char. 32): (0) present; (1) absent. char. 23): (0) contact with peripherals X 32. Fusion of gulars (Hirayama et al., 2001: and XI; (1) contact with peripheral XI only. char. 33): (0) absent; (1) present. 23. Shape of pygal (Brinkman and Nicholls, 33. Size and medial contact of extragulars 1993: char. 4d): (0) longer than wide; (1) (modi®ed from Brinkman and Nicholls, wider than long. 1993: char. 4a; Hirayama et al., 2001: char. 24. Anterior contacts of vertebral I (modi- 32): (0) extragulars small or absent, and, if ®ed from Hirayama et al., 2001: char. 20): present, do not meet medially; (1) extra- (0) anterior side very wide, in contact with marginal II; (1) anterior side moderately gulars elongate, in medial contact with an- wide, in contact with marginal I; (2) ante- other, thus hindering a contact between gu- rior side constricted, primarily in contact lars and humerals. with cervical only. 34. Broad dorsal extension of gulars onto 25. Contacts of vertebral V with marginals thickened anterior plastral lip (Hirayama X and XI (modi®ed from Hirayama et al., et al., 2001: char. 35): (0) absent; (1) pres- 2001: char. 27): (0) vertebral V only in ent. contact with half the length of marginal XI; 35. Position of gulars and extragulars rela- (1) vertebral V contacts full length of mar- tive to entoplastron: (0) scutes do not ginal XI and may even contact marginal X. overlap entoplastron; (1) scutes overlap 26. Position of vertebral V relative to supra- onto entoplastron. pygals (modi®ed from Hirayama et al., 36. Humero-pectoral sulcus (Hirayama et al., 2001: char. 26): (0) vertebral V only par- 2001: char. 34): (0) does not intersect en- tially covers suprapygals; (1) vertebral V toplastron; (1) intersects entoplastron. fully, or almost fully, covers the suprapy- COMMENTS: Scoring of Zangerlia testudi- gals. nimorpha changed from ``1'' to ``0''. 27. Position of vertebral V relative to pe- 37. Inframarginals (Hirayama et al., 2001: ripheral X (modi®ed from Hirayama et al., char. 29): (0) four or three pairs; (1) two 2001: char. 26): (0) vertebral V does not pairs; (2) absent. COMMENTS: Scoring of reach peripheral X; (1) vertebral V clearly Zangerlia neimongolensis changed from covers part of peripheral X. ``0/1'' to ``0''. 28. Sulcus between pleural I and marginals 38. Expansion of the ventromedial edge of II and III (modi®ed from Hirayama et al., 2001: char. 25): (0) clearly situated on pe- marginal VI (Brinkman and Nicholls, ripherals; (1) situated on or near suture of 1993: char. 1; Hirayama et al., 2001: char. peripherals and costals or clearly situated 30): (0) absent; (1) present. COMMENTS: on costals. Scoring of Basilemys praeclara changed 29. Sulcus between pleural III and margin- from ``1'' to ``?''. als VII±IX (modi®ed from Hirayama et al., 39. Participation of pectoral to rim of axil- 2001: char. 25): (0) clearly situated on cos- lary notch (modi®ed from Hirayama et al., tals; (1) situated near suture of peripherals 2001: char. 31): (0) present; (1) absent. and costals; (2) clearly situated on periph- 40. Geographical distribution: (0) North erals. America; (1) Asia. 2005 JOYCE AND NORELL: LATE CRETACEOUS TURTLE 19

APPENDIX 2

TAXON±CHARACTER MATRIX Complete lists of all issues of the Novitates and the Bulletin are available at World Wide Web site http://library.amnh.org/pubs. Inquire about ordering printed copies via e-mail from [email protected] or via standard mail from: American Museum of Natural History, LibraryÐ Scienti®c Publications, Central Park West at 79th St., New York, NY 10024. TEL: (212) 769- 5545. FAX: (212) 769-5009.

a This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).