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PaleoBios 23(3):21–35,23(3):21–35, December 115,5, 2003 © 2003 University of California Museum of Paleontology

The fi rst report of hard-shelled sea (Cheloniidaesensu lato) from the of California, including a new ( hutchisoni) with unusually plesiomorphic characters

SHANNON COLLEEN LYNCH1and JAMES FORD PARHAM2 1Department of Plant Pathology, 1 Shields Avenue, 371 Hutchison Hall; University of California, Davis; Davis, California 95616; [email protected]. 2University of California Museum of Paleontology, 1101 Valley Life Sciences Building; University of California, Berkeley; Berkeley, California 94720; [email protected]

In this paper we describe the fi rst cheloniid from the Miocene (Barstovian) of California, USA. All specimens are from Sharktooth Hill, Round Mountain Silt Member of the marine , in Kern County. The material includes two species: (1) a form with a sculptured carapace (cf. Syllomus) known from a single specimen; (2) a form with unusually plesiomorphic characters including a wide plastron, a -like-like humerhumerus,us, femoral trochanters separated by a deep fossa, a broad sutural contact between the vomer and premaxillae on the palatal surface, and a single facet on the anterior end of the eighth cervical vertebra. This second can be differentiated from other cheloniid taxa and so is named a new species, Euclastes hutchisoni. A cladistic analysis of 13 cheloniid taxa and 34 morphological characters suggests a phylogenetic position of Euclastes hutchisoni far-removedfar-removed from the living cheloniids. Euclastes hutchisoni appears to be the last member of a - radiation of durophagous stem cheloniids.

INTRODUCTION mals. Specimens of hard-shelled sea turtles ( sensu In this paper we describe the fi rst cheloniid turtle fossils lato) are relatively more rare. from the Miocene of California, USA. The material includes of hard-shelled sea turtles (Cheloniidae sensu several specimens of a new species of cheloniid sea turtle, lato) Euclastes hutchisoni. In addition to E. hutchisoni, wewe ddescribeescribe one specimen (UCMP V69169/88516) that superfi cially re- The taxonomy of hard-shelled sea turtles is constantly sembles Syllomus Cope 11896.896. All of tthehe specimens descrdescribedibed changing. For the sake of clarity, we provide a detailed below are from Sharktooth Hill, Round Mountain Silt Mem- explanation of the taxonomy used by this study. We use ber of the marine Temblor Formation, in Kern County, Cali- a phylogenetic taxonomy (de Queiroz and Gauthier 1990, fornia. Sharktooth Hill is considered to be middle Miocene 1992) a system previously restricted to a few turtle studies (Lee 1995, 1997, Parham and Fastovsky 1997). Parham (~13–15 m.y.o., Barstovian North American land age, “Temblor” provincial molluscan stage, Relizian or Lu- and Fastovsky (1997) phylogenetically codifi ed Cheloniidae isian foraminferal stage; Evernden et al. 1964, Berggren and Bonaparte 1832 to match the usage of the recent systematic Van Couvering 1974, Barnes 1976, 1978, Repenning and works (Hirayama 1992, 1994, Hirayama and Chitoku 1996, Tedford 1977, Barnes and Mitchell 1984). Hirayama 1998). They gave Cheloniidae a stem-based defi - Sharktooth Hill well known for its abundant shark teeth nition as “those turtles that share a more recent common and marine mammal specimens (Mitchell 1965, 1966, Mitch- ancestor with extant marine turtles (exclusive of Dermochelys) ell and Tedford 1973, Barnes 1976). The only preexisting than with Dermochelys or .” Parham and Fastovsky work on marine turtle material from Sharktooth Hill is a (1997) called the crown group of cheloniids “Cheloniinae”. short note by Gilmore (1937). In that paper, Gilmore erects Following the arguments presented by Rowe and Gauthier a new , Chelonia? californiensis, forfor an isolatedisolated turtleturtle (1992), we feel that the crown group should receive the most femur (CAS 4379). The fi gures of this specimen show that common name: Cheloniidae. Unfortunately, this causes an it belongs to a dermochelyid turtle close to “” inconsistency with previously published systematic works. We calvertensis Palmer 1909 from the Calvert Formation of compromise by using Cheloniidae sensu lato fforor tthehe sstem-tem- Maryland, a formation that is approximately the same age defi nition of Cheloniidae and Cheloniidaesensu stricto forfor thethe as Sharktooth Hill (Ray 1976, Barnes and Mitchell 1984). crown-group name. This system was fi rst used by Lapparent Personal observation of large numbers of undescribed speci- de Broin (2001). mens of a large dermochelyid from Sharktooth Hill (at the , OsOsteopyginae,teopyginae, and Euclastes—The name Os- BVM) support the hypothesis that the Temblor and Calvert teopygis CopeCope 18701870 andand itsits derivativesderivatives (Osteopyginae(Osteopyginae ZangerlZangerl dermochelyids are conspecifi c, but detailed study is needed. 1953, Osteopygidae Gaffney and Meylan 1988) have long The fragmentary remains of this leatherback are a common been associated with specimens of and component of Sharktooth Hill sediments, though consider- Paleogene cheloniid s.l. marine turtles showing adaptations ably less abundant than the sharks (teeth) or marine mam- for durophagy. During ongoing studies of eucryptodiran 22 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003 turtles, one of the authors discovered that the type speci- Institutional Abbreviations: AMNH, American Mu- men of Osteopygis (AMNH(AMNH 1485,1485, a shell)shell) is not cheloniid s.l., seum of Natural History, New York; ANSP, Academy of but represents a “macrobaenid” (Parham unpublished data). Natural Sciences of Philadelphia; BPBM, Bernice P. Bishop “Macrobaenids” are poorly known turtles that fi rst appear in Museum; BVM, Buena Vista Museum of Natural History; the Early Cretaceous of Asia and persist until the Paleocene CAS, Museum of the California Academy of Science, Pale- of Asia and North America (Sukhanov 2000, Parham and ontology; CNHM, Field Museum of Natural History (Chi- Hutchison in press). The skull of Osteopygis isis unknown.unknown. cago Natural History Museum); GHUNLPam, la Cátedra Thus, we do not use Osteopyginae or Osteopygidae for the de Geología Histórica y Regional, Universidad Nacional de assemblage of taxa that included the skull material referred la Pampa; IGPS, Institut für Geologie und Paläontologie to Osteopygis aandnd fi v eve m omonotypicnotypic s kskull-basedull-based g egeneranera ( Euclastes( der Universität Salzburg; I.R.Sc.N.B., Institut Royal des Cope 1867, Glossochelys SeeleySeeley 1871,1871, Erquelinnesia Dollo Sciences Naturelles Belgique; LACM, Los Angeles County 1887, Osteopygoides Karl,Karl, TichyTichy andand RuschakRuschak 1998,1998, andand Pam- Museum of Natural History; SFMF, Forschungsinstitutund paemys de la FuenteFuente and Casadío 2000). GivenGiven thethe overalloverall Museum Senckenberg Frankfurt am Main; S.M.C., Sedg- similarity of the material upon which these generic names wick Museum, Cambridge; UCMP, University of California are based, we place all of these skull genera into the oldest Museum of Paleontology, Berkeley; USNM, United States available name: Euclastes (see(see AppendixAppendix I).I). WeWe dodo thisthis becausebecause National Museum. the sea turtle skulls referred to Osteopyginae require names and because it is not helpful to create additional monotypic SYSTEMATIC PALEONTOLOGY genera for Euclastes hutchisoni, Osteopygis roundsi Weems TESTUDINES Batsch 1788 1988, and the skull material traditionally referred to Osteo- Cope 18681868 pygis emarginatus Cope 1868. Our phylogenetic defi nition CHELONIIDAE sensu lato BonaparteBonaparte 11832832 of Euclastes is “t“thosehose ttaxaaxa tthathat sharsharee a mormoree rrecentecent common EUCLASTES Cope 1867 ancestor with Euclastes platyops Cope 18671867 tthanhan ttoo Chelonia Emended diagnosis—Unlike Toxochelys Cope 11873873 and Brongniart 1800, Argillochelys Lydekker 1889a, or Puppigerus Dollo 11903903 based on tthehe prpresenceesence of a secondarsecondaryy Cope 1870”. Euclastes isis diagnoseddiagnosed byby thethe derivedderived featuresfeatures ofof palate. Different from Ctenochelys ZZangerlangerl 11953953 bbyy tthehe eextentxtent an extensive secondary palate and wide skull (Zangerl 1953, of the secondary palate. Distinguished from other cheloniids Fastovsky 1985, Gaffney and Meylan 1988, Hirayama 1994, s.l. based on: (1) broad skull; (2) low skull profi le; (3) broad Hirayama and Chitoku 1996, Parham and Fastovsky 1997, and fl at palatal surface; (4) low tomial ridge; (5) wide, fl at Hirayama 1998), as well as the retention of plesiomorphic dentary; (6) dentary with an elongated symphysis. features such as a broad suture between the vomer and the premaxillae, unfused trochanters of the femora, humerus EUCLASTES Cope 1867 with a proximal lateral process, plastra wider than long, and a EUCLASTES HUTCHISONI sp. nov. single anterior facet on the eighth cervical vertebra. In many Holotype—LACM 103351 (Figs. 2–4), a nearly complete respects, Euclastes is evocative of the living Caretta Merrem skull and mandible. 1820, though Caretta exhibits all the derived features of the Referred Materials—Figures 4–8. BVM 0810, a partial crown group (Cheloniidae s.s.) and none of the plesiomor- skeleton including a mandible, a partial plastron, three phies just mentioned. Parham and Fastovsky (1997) noted cervical vertebra elements, four costals, a pygal, and seven that the supposedly derived features of Euclastes might be peripherals; BVM 0806, BVM 0805 and UCMP V69169/ the result of functional convergence for durophagy, but there 98202, all dentaries; BVM 0532, left humerus; BVM 0807, are no data to support that hypothesis at this time. complete humerus; BVM 0472, nearly complete humerus, Two species incorrectly referred to Osteopygis warrant more missing the distal end; UCMP V6024/65617, complete hu- detailed taxonomic discussion. Osteopygis sculptus StaescheStaesche merus; UCMP V6843/88343, complete humerus; UCMP 1929, from the Paleocene of Argentina, is based on the V6843/86024, proximal humerus; UCMP V68131/85318, material of a pleurodiran turtle (de Broin and de la Fuente proximal humerus fragment; UCMP V68131/97116, hu- 1993). Apparently unaware of this, Karl et al. (1998) tenta- merus; UCMP V6323/88367, proximal humerus; UCMP tively referred a partial skull of a cheloniid s.l. (SFMF Nr. R V69169/88379, proximal humerus; BVM 0471, large com- 4151) from the Late Cretaceous Quiriquina Formation of plete femur; BVM 0535, femur; BVM 0809, proximal femur, Chile to Osteopygis aff. sculptus. We refer to this specimen and BVM 0808 proximal femur; UCMP V6323/88364, femur; an isolated dentary referred to Osteopygis byby GaspariniGasparini and UCMP 1292/61576 proximal femur. Biro-Bagoczky (1986) as the Quiriquina Euclastes. Locality and Horizon—All specimens are from Shark- Osteopygis salisburgensis Karl 1996 is based on a partial shell tooth Hill, Kern County, California. Round Mountain Silt from the of Austria that does not match the “macro- member of the Temblor Formation, middle Miocene (Bar- baenid” Osteopygis. We consider this species to be a cheloniid stovian). The holotype is from LACM locality 3162. s.l. of indeterminate affi nities. Though the generic assignment Diagnosis—Unlike the four of the six named species of is clearly wrong, the specifi c epithet may be valid. Euclastes (Euclastes platyops CopeCope 1867,1867, Euclastes gosseleti LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 23

[Dollo 1886], Euclastes roundsi [Weems 1988], Euclastes pris- DESCRIPTION OF EUCLASTES HUTCHISONI cus [Karl, Tichy, and Ruschak 1998]) based on the presence Description of Holotype, LACM 103351 (Figs. 2–4) of an incised palatal surface of the premaxillae. Secondary palate not as extensive as Euclastes meridionalis (de la Fuente The type of Euclastes hutchisoni is a skskullull and mandible and Casadío 2000). Skull not as high or wide as Euclastes (LACM 103351). Although the braincase and otic region are planimenta OwenOwen 11842842 and orbits nonott as dorsalldorsallyy facing. almost entirely missing, LACM 103351 provides adequate Etymology—The specifi c epithet, hutchisoni, isis f foror J J.. detail for description and determination of taxonomic af- Howard Hutchison of the University of California Museum fi nities. The left side of the skull roof (the cheek region) is of Paleontology, a respected fossil collector, artist, and expert missing, but the right side of skull is mostly complete. The on fossil turtles, moles, and shrews. skull (14.5 cm preserved length) is broad and subtriangular in dorsal view, widest at the postorbitals (11.5 cm). The CHELONIIDAE sensu lato BonaparteBonaparte 11832832 posterior portion of the skull roof is represented by the cf. SYLLOMUS AEGYPTIACUS Lydekker 1889b parietals posteriorly and a small portion of a broken crista Trachyaspis aegyptiaca LydekkerLydekker 11889b889b supraoccipitalis along the midline of the skull. The apetura Syllomus crispatus Cope 18961896 narium externa face anterodorsally. The orbits are large and Peritresius virginianus Berry and Lynn 1936 face anterolaterally. In lateral view, the skull has a low profi le Kurobechelys tricarinata ShikamaShikama 11956956 relative to modern forms. Ventrally, a complete secondary Material—UCMP V69169/88516, fragment of costal palate is preserved. with distinct sculpturing. Skull roof (Prefrontal, Postorbital, Frontal, Parietal, Because the costals referred to E. hutchisoni (Fig. 6B) lack Jugal)—The prefrontal borders the anterodorsal rim of the sculpture, we conclude UCMP 88516 represents another orbit and the posterior rim of the nares (if nasals are ab- taxon. UCMP 88516 exhibits a dorsal sculpturing (Fig. 1) sent). It contacts the maxilla anterolaterally and the frontal similar to that seen in Syllomus Cope 1896. The name Syllomus posteromedially. Together, the prefrontals form a “V” with is commonly used to refer to an enigmatic species of pseu- the open end posterior. The key shaped fi ssura ethmoidalis dodont cheloniid s.l. known from Miocene deposits world- is visible anteriorly, and is dorsally and laterally bound by the wide (Weems 1974, 1980, Zug 2001). Lapparent de Broin prefrontal descending processes. Careful inspection indicates (2001) raises the possibility that the name Trachyaspis vonvon the presence of a suture near anterior rim of the prefrontals, Meyer 1843 may be an objective senior synonym of Syllomus. but posterior to the dorsal edge of the nasal opening. Despite However, the type species of Trachyaspis (Trachyaspis lardyi additional preparation of the underside of the nasal region, von Meyer 1843) is only known from a few shell fragments. this “nasal suture” is only visible in dorsal view, making Lacking more complete material, or even a more detailed the presence or absence of nasals somewhat equivocal. The comparison, we tentatively retain the name Syllomus while posterior rim of the apetura narium externa and the anterior encouraging future investigation into the problem. rim of the prefrontals border the “nasals.” The frontals are pentagonal in shape and are bordered by the postorbital laterally, the parietal posteriorly, and prefron- tals anterolaterally. The frontal is eliminated completely from orbital contact by the prefrontal and postorbital. In ventral view, the descending processes of the frontals form the lateral wall of the sulcus olfactorius. Although both postorbitals are damaged, the contact with the prefrontals, frontals, and parietals is visible. The postorbital forms the posterior rim of the orbit. The ventral contact with the jugal has been reconstructed on the right side. Ventrally, a transverse ridge extends posteromedially from the postorbital onto the parietal. Tong and Hirayama (2002) discuss this feature in Tasbacka NessovNessov 19871987 and note that unlike Chelonia, the ventral postorbital ridge in Tasbacka is prominentprominent and extendsextends ontoonto thethe parietal.parietal. The ridge in LACM 103351 is thick and appears to be similar to that described for Tasbacka (Tong(Tong and HirayamaHirayama 2002). Unfortunately, it is diffi cult to determine relative prominence 1 cm from fi gures. With the exception ofE. hutchisoni, Tasbacka, and Chelonia, this postorbital ridge is not described for other cheloniids sensu lato. Inspection of another modern cheloniid Fig. 1. cf. Syllomus, UCMP 88516,88516, prproximaloximal coscostaltal fragment in (Caretta, UCMP 119069) reveals that the postorbital ridge dorsal view showing sculptured surface. is weak, but still extends posteromedially into the parietal. 24 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003

At the parietal, however, it is more of a swelling, not a dis- The parietal is almost entirely preserved. It is a broad, tinct ridge. trapezoidal bone that contacts the frontal anteriorly and the postorbital laterally. Taken together, the parietals form the majority of the skull roof. Ventrally, the dorsal portion of the descending processes of the parietals is preserved. These processes extend along the entire length of the preserved parietals, contacting the supraoccipital posteriorly. Only the right jugal is preserved. It makes up the postero- ventral rim of the orbit in lateral view. Sutures are not read- ily visible along the orbital wall, but the jugal undoubtedly contacts the maxilla and palatine. In lateral view, jugal contact with the postorbital is missing, but anteriorly it contacts the maxilla below the orbit. Basicranium (Supraoccipital, Exoccipital, Prootic, Opisthotic)—The basicranium of LACM 103351 is largely missing. The preserved portions entail the anterior portion A of the supraoccipital and parts of the left exoccipital, prootic, and opisthotic. The preserved contacts of the supraoccipital include the parietals dorsally and the remaining elements lateroventrally. Most of the crista supraoccipitalis is not preserved. The ventral surface of the supraoccipital forms the posteromedial roof of the cavum cranii. This portion of the supraoccipital is smooth and U-shaped, formed by two venterolateral processes. On the left side, the venterolateral process articulates with the exoccipital, prootic, and opisthotic. These bones are missing on the right side, but the sutural connections are preserved,

1 cm

B

A

C 5 cm

Fig. 2. Holotype cranium of Euclastes hutchisoni (LACM(LACM 103351). A. Dorsal view. B. Ventral View. C. Right lateral view. Visible sutures are highlighted. Abbreviations: c.l., cavum laby- B rinthicum; ex, exoccipital; fr, frontal; ju, jugal; mx, maxilla; n?, probable nasal; op, opisthotic; pa, parietal; pal, palatine; pmx, Fig. 3. Euclastes hutchisoni, LACMLACM 1103351,03351, holoholotype,type, tthehe ffeed-eed- premaxilla; po, postorbital; pref, prefrontal;prefrontal; pro, prootic; sup, ing apparatus of. A. Detailed view of the palate. B. Detailed view supraoccipital; vo, vomer. of the dentary triturating surface. LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 25 as is the dorsal surface of the cavum labyrinthicum. this shelf that forms the anterior rim of the apetura narium The right exoccipital is damaged so that only its dorsal half interna appears to have a rough, unnatural edge. In Euclastes is preserved. The contribution to the condylus occipitalis is gosseleti, Tasbacka, Caretta, and Lepidochelys Fitzinger 1843, present. Lateral to this is a hypoglossal nerve foramen, still the posterior edge of the vomerine pillar is anterior to the fi lled with sediment. The suture between the exoccipital and posterior termination of the choanae (Zangerl 1971, 1980, the opisthotic is barely visible. The lateral process of the Tong and Hirayama 2002). We cannot determine the condi- opisthotic (which contacts the jugal and squamosal) is pres- tion for most other taxa, but it may have phylogenetic value. ent. The anteromedial surface of the opisthotic forms the Nevertheless, E. hutchisoni dif differsfers fromfrom Euclastes gosseleti, posterolateral wall of the cavum labyrinthicum. Tasbacka, Lepidochelys, aandnd Caretta, in which the undershelv- Most of the prootic is preserved. Posteriorly, the prootic ing of the nasal passages is more pronounced (Zangerl 1971, forms the anterior wall cavum labyrinthicum. In modern sea 1980, Tong and Hirayama 2002). Although the anterior turtles the prootic has a swollen appearance and the antero- rim of the apetura narium interna is apparently damaged in lateral wall of the prootic is convex. In LACM 103351, the LACM 103351, it was probably positioned anterior to the anterolateral wall of the prootic lacks this convexity. Laterally, anterior rim of the fossa temporale inferior. the path of stapedio-temporale canal is visible. The premaxillae form the anterior rim of the apetura nar- Palate (Premaxilla, Maxilla, Vomer, Palatine)—The ho- ium externa. In ventral view there may be a remnant suture lotype has a complete secondary palate and a relatively low between the premaxillae, but they are fused for the majority tomial ridge (Fig. 3A). The triturating surface of the palate of their contact. Ventrally, the premaxillae are bordered by itself is mostly fl at and heavily perforated by nutrient foram- the maxillae laterally, and the vomer posteriorly. The ventral ina. The ventrally exposed shape of the vomer is rectangular surfaces of the premaxillae and vomer are deeply incised with and of constant width throughout its length. The vomer a groove that indicates the occlusal pattern of the keratinized broadly contacts the premaxillae anteriorly, the maxillae an- beak that covered the dentary (Figs. 3, 4). The groove is terolaterally, and the palatines posterolaterally. The vomerine anchor-shaped and the area between the arms and shaft have pillar and dorsal plate of the vomer extend just beyond the ventrally projecting processes. posterior edge of the ventral plate of the vomer. Conse- The maxilla is a large bone that, in lateral view, forms the quently, the nares are visible in ventral view. It is possible anteroventral and anterior edge of the orbit. In lateral view, that the posterior portion of the ventral plate of the vomer it contacts the jugal posteriorly, the premaxilla anteriorly, the is damaged. We suspect this to be true because the area of prefrontal posterodorsally, and borders the apetura narium

A C

D 1 cm B

Fig. 4. Euclastes hutchisoni dentaries.dentaries. A. LACM 103351, dorsal view. B. LACM 103351, left lateral view, the anterior suture of the surangular is highlighted. C. BVM 0810, dorsal view. D. BVM 0805, dorsal view. 26 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003

bra elements, four costals, a pygal, and seven peripherals. The dentary of BVM 0810 matches the morphology of LACM 103351. We recognize the problems that tenuous referrals may cause in the future and so urge future students to ques- tion our association. However, the unusually plesiomorphic characters in the postcrania of BVM 0810 (see below) is consistent with the unusually plesiomorphic characters of the type skull (see above). Dentary—The symphyseal convexity of BVM 0810 (Fig. 3D) is similar to that of the holotype. This convexity is de- spite the presumably younger age class, of BVM 0810 (1.8 cm symphysis length compared to 3.8 cm in the holotype). Vertebrae—BVM 0810 includes two vertebrae, an eighth 1 cm cervical and a fi rst thoracic (Fig. 5). These elements are A B typically cheloniid. The eight cervical is procoelous. The anterior facet is singular, a character shared by Ctenochelys and Argillochelys. The majority of cheloniids s.l., including all Fig. 5. Euclastes hutchisoni, BVMBVM 080810,10, vvertebrae.ertebrae. A. Eighth cervical, anterior view. B. First thoracic, ventral view. of the crown taxa, have a doubled articulation between the eighth and seventh cervicals. Plastron—BVM 0810 includes a partial right hypoplas- externa laterally. On the orbital fl oor, the maxilla hosts a tron and two unidentifi able plastron fragments (Fig. 6A). horizontally trending foramina orbitonasale. The maxilla No scale sulci are visible. The hypoplastron shows that, if presumably contacts the prefrontal, vomer, and jugal on the whole, the plastron of BVM 0810 would be wider than long. orbital fl oor, but the sutures are obscured. In ventral view, the This character is shared by HaHayy 11908,908, a poorpoorlyly maxilla contacts the premaxilla and vomer medially, and the known turtle from the Miocene of New Jersey and Maryland palatine posteromedially. The maxilla forms the posterolateral (Zangerl and Turnbull 1955, Weems 1974). margin of the secondary palate and a signifi cant portion of Costal Elements—Four costal elements from the shell of the triturating surface of the palate. BVM 0810 are present, all of which lack dorsal sculpturing The palatine contacts the maxilla laterally, the vomer an- (Fig. 6B). Additional specimens of unsculptured costals are teromedially, and forms the anterolateral rim of the apetura housed in the collections of the UCMP. We do not refer these narium interna. The palatine is of constant width. It extends specimens to E. hutchisoni because unsculpunsculpturedtured coscostalstals araree laterally from the posterior portion of the vomer and then widely distributed feature of Cheloniidae s.l. The rib heads of projects posteriorly. Consequently, there is a distinct break in Euclastes hutchisoni areare moremore pronouncedpronounced and extendextend moremore the slope of the palato-maxillary suture. The posterior-most ventrally than those of living cheloniids (Fig. 6C). edge of the palatines is damaged so the ultimate extent of Referred Isolated Specimens the palatines is unknown. Dorsally, the anterior sutures of the palatines are not distinct, but they do contact the vomer Nineteen isolated specimens are referred to Euclastes anteromedially and the maxillae laterally. hutchisoni (three dentaries, 16 limb elements). Mandible—The dentarydentary is broadbroad and fl atat (F(Fig.ig. 4A).4A). TheThe Dentaries—In addition to the type specimen and BVM symphyseal length (3.8 cm) is 28.6% of the total mandible 0810, three dentaries from Sharktooth Hill bear a remark- length (13.3 cm). The triturating surface is extensive, but the able similarity to the type specimen: BVM 0806 (2.7 cm posterior edge does not reach a hypothetical line connecting symphysis length), BVM 0805, a large specimen (6.0 cm the foramen dentofaciale majus on each side (Zangerl 1971). symphysis length); UCMP 98202, a fragment. The primary The width at the level of the dentofaciale foramen is 7.0 cm. morphological difference between these specimens is on the Posteriorly, there is a sagittal swelling of the symphysis. A dorsal crushing surface. The largest jaw (BVM 0805; Fig. medial, triangular-shaped convexity divides the triturating 4C) possesses a completely fl at triturating surface, lacking the surface into concave halves. There is no evidence of the sagittal swelling seen on the holotype and other specimens. keratinous beak that occluded with the incised palate. Pos- Humeri—Ten isolated humeri are referred to Euclastes teromedially, the sulcus cartilaginis meckelii is present. The hutchisoni onon thethe basisbasis ofof theirtheir unusuallyunusually plesiomorphicplesiomorphic surangular does not extend anteriorly onto the dentary in morphology (see Referred Materials above). One entirely lateral view (Fig. 4B). preserved humerus (UCMP 65617; Fig. 7B) is used to il- lustrate the humeral morphology of E. hutchisoni. All referred Description of BVM 0810 specimens match UCMP 65617 in general morphology. BVM 0810 is the most complete specimen of E. hutchisoni, UCMP 65617 possesses a relatively narrow and cylindrical comprising a mandible, a partial plastron, three cervical verte- shaft viewed in dorsal and ventral aspect. The shaft is notice- LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 27

A

1 cm

C B

Fig. 6. Euclastes hutchisoni, BVMBVM 080810,10, shell pieces. A. Right hypoplastron, ventral view. B. Costal fragment, dorsal view. C. Differ- ent costal fragment, posterior view. ably curved in lateral view and the distal articular surface of Referred Materials above). BVM 0471 (Fig. 8) is used to the humerus is reduced. While displaying the morphology of demonstrate the morphology seen in all referred femora. a marine turtle, the proximal end of the humerus is still less The shaft is narrow and laterally curved. The head is round derived compared to those of living cheloniids. The medial and extends further anteriorly than the trochanters. The process is elongated proximally, a character observed in sea trochanters are separated by a deep fossa. In cheloniids s.s., turtles. But unlike living cheloniids s.l., the proximal extent a ridge connects the femoral trochanters. of the medial process is subequal to the head in ventral view. The lateral process of UCMP 65617 also differs from those PHYLOGENETIC ANALYSIS of modern cheloniids in its more proximal position. In Che- In to test the phylogenetic position of Euclastes loniidae s.s. the process shifts further distally onto the shaft, hutchisoni, wewe performedperformed a cladisticcladistic analysisanalysis ofof 3131 osteologicalosteological giving the supracoracoideus muscle increased leverage. The characters for 13 of the better-known cheloniids s.l. (Table lateral process of UCMP 65617 is shifted distally relative to 1). Our analysis is based on Parham and Fastovsky (1997). the primitive condition, but its medial half is still adjacent to That data set included 24 characters and 13 taxa. For both the intertubercular fossa. Therefore, like the early cheloniids studies, included taxa are restricted to those known from Toxochelys and thethe LophochelyinaeLophochelyinae ZangerlZangerl 1953,1953, E. hutchi- skull, shell, and limb material. We do not include the Horn- soni retains a level of locomotory specialization intermediate erstown Euclastes (known(known onlonlyy frfromom skskullull matmaterial),erial), but add between the plesiomorphic non-pelagic condition and the Euclastes hutchisoni. Toxochelys andand Ctenochelys areare designateddesignated derived condition of living sea turtles (Fig. 7). as outgroups. In our matrix, character #13 of Parham and Femora—Six femora are referred to Euclastes hutchisoni Fastovsky (1997) is divided into two characters. The exclusion based on their unusually plesiomorphic morphology (see of the Hornerstown Euclastes rrendersenders twtwoo ootherther ccharactersharacters 28 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003

A

A B

Fig. 8. Euclastes hutchisoni, BVMBVM 00471,471, rrightight ffemur.emur. A. Anterior view. B. Ventral view. B Cranial 1. Secondary palate: (0) present; (1) absent (=Parham and Fastovsky 1997: #1). Originally, this character had three character states: (0) absent; (1) present; (2) extensive. This character has been modifi ed to recognize the simple presence or absence of a secondary palate. 2. Foramen palatinum posterius: (0) wide; (1) lost (=Par- ham and Fastovsky 1997: #2). 3. Contact of vomer with premaxillae: (0) broad; (1) reduced (=Parham and Fastovsky 1997: #3). Parham and Fastovsky (1997) state that all cheloniids s.s., except Nata- tor McCulloch 1908, have a reduced contact between the C premaxillae and the vomer. However, Natator waswas incorrectlyincorrectly coded as having the derived state in their matrix. Fig.Fig. 77.. Cheloniid s.l. turtles,turtles, lefleftt humerhumerii in dorsal, vventral,entral, and 4. Foramen caroticum laterale much larger than foramen lateral views. A. Ctenochelys sp., CNHM PR 27334. B. Euclastes anteris canalis caroticus interni: (0) absent; (1) present (=Par- hutchisoni, UCMP 65617.65617. C. Chelonia, UCMP 186567. ham and Fastovsky 1997: #4). 5. Dentary: (0) fl at triturating surface; (1) lingual ridges present; (2) ridge along entire length of symphysis (=Parham from Parham and Fastovsky (1997), #5 and #7, phylogeneti- and Fastovsky 1997: #6). cally uninformative. Additional alterations to the matrix are 6. Tomial ridge: (0) pronounced; (1) low (=Parham and noted with each character where necessary. The data were Fastovsky 1997: #7). analyzed using the parsimony algorithm of PAUP* 4.0b3a 7. Surangular extending anteriorly into dentary: (0) absent; (Swofford 1998). (1) present. (=Parham and Fastovsky 1997: #8). 8. Shape of the anterior portion of the vomer: (0) con- Character List stant width; (1) variable width (=Parham and Fastovsky: The distribution of the following 31 characters for 13 che- 1997: #9). loniid s.l. taxa (incl. E. hutchisoni) can be found in Table 1. 9. Prefrontal scutes: (0) one pair; (1) two pair (=Parham and Fastovsky 1997: #10). LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 29

10. Process pterygoideus externus: (0) large; (1) reduced. The process pterygoideus externus is completely lost within 0 0 0 1 1 0 0 0 0 0 0

— — the and the protostegid WielandWieland 31 1896 (Hirayama 1994). Within Cheloniidae s.l., this process 0 0 0 1 0 0 1 1 1 0 0 0 — 30 is still present, but reduced in derived forms. Natator is tthehe 0 0 0 0 0 0 2 2 2 1 2 2

— only living hard-shelled sea turtle in which the process ptery- 29 goideus externus is large (Zangerl et al. 1988). 0 0 0 0 0 0 0 0 0 0 1 1 — 28 11. Direction of the orbits: (0) dorsolaterally facing; (1) 0 0 0 0 0 0 0 0 0 0 1 1

— laterally facing. The direction of the orbits mainly differs 27 among the durophagous cheloniids. The orbits of Euclastes 0 0 0 1 1 1 1 1 1 1 1 1 — 26 gosseleti, Euclastes hutchisoni, Tasbacka and modermodernn durduro-o- 0 1 1 1 1 2 2 2 2 2 2

— — phagous cheloniids face laterally (Zangerl 1971, Zug 2001, 25 Tong and Hirayama 2002). Euclastes platyops and thethe Horn-Horn- 0 0 0 0 1 1 1 1 1 1 1 1 1 24 erstown Euclastes rretainetain tthehe prprimitiveimitive condition (Ha(Hayy 11908,908, 1 0 0 0 1 1 1 1 1 1 1

— — Fastovsky 1985). 23 12. Skull shape: (0): Moderate width; (1) Broad; (2) 0 0 1 1 1 1 1 1 1 1 1 — — 22 Narrow and elongate. Skull shape is undoubtedly correlated

0 0 0 0 0 0 0 1 1 1 1 1 1 to diet. For Euclastes and the carettines, a broad skull is 21 associated with fl at dentaries, a specialization for a duro- 0 0 1 1 1 1 1 1 — — — — — 20 phagous diet. 0 0 0 0 1 1 1 1 1 1 1

— — 13. Fused premaxillae: (0) absent; (1) present. Originally 19 autapomorphic for Euclastes gosseleti (Zangerl 1971), the 0 0 0 1 1 1 1 1 1 0 0 0 — 18 fused premaxillae are now a synapomorphy for E. gosseleti 0 0 0 0 0 0 1 1 1 1 1 1

— and E. hutchisoni. 17 0 0 0 0 0 0 0 0 0 1 1 1 — 16 Non-Shell Post Cranial 0 0 0 0 0 1 1 1 1 1 1 modifi ed from Prham and Fastovsky (1997). Fastovsky and Prham ed from modifi

— — 14. Dorsal process of scapula forming relatively wide 15 s.l. angle with acromion: (0) absent; (1) present (=Parham and 0 0 0 0 0 0 1 1 1 1 0 0 — 14 Fastovsky 1997: #11).

0 0 1 1 0 0 0 0 0 0 0 0 0 15. Metischial processes: (0) pronounced; (1) reduced. 13 (=Parham and Fastovsky 1997: #12). 0 0 1 1 0 0 2 0 0 0 2 1 0 12 16. Femoral trochanters: (0) separated by a fossa; (1) fossa

0 0 1 1 1 1 1 1 1 1 1 1 1 obliterated (=Parham and Fastovsky 1997: #13 in part). We 11 divide the femoral trochanters into two characters. 0 0 1 0 0 1 0 1 1 1 1 — — 10 17. Femoral trochanter ridge: (0) not complete; (1) 0 0 0 0 0 0 1 1 1 9

— — — — complete, without a notch (=Parham and Fastovsky 1997: #13 in part). 0 0 1 0 0 1 1 1 1 1 1 1 8 — 18. Tibial pit for pubotibialis and fl exor tibialis internus 0 0 0 0 0 0 0 0 1 1 1 1 1 7 muscles: (0) absent; (1) present (=Parham and Fastovsky 1997: #15). 0 0 1 1 0 0 0 0 0 0 0 0 0 6 19. Centra of the seventh cervical vertebra: (0) procoelous; 0 0 0 0 2 0 0 2 1 2 1 0 0 5 (1) platycoelous (=Parham and Fastovsky 1997: #16). 20. Articulations of fi rst and second digits: (0) movable; 0 0 1 1 0 1 1 1 1 1 1 1 4 — (1) immovable (=Parham and Fastovsky 1997: #17). 0 0 0 0 0 0 0 0 1 1 1 1 3

— 21. Humerus with V-shaped or triangular lateral process: (0) absent; (1) present (=Parham and Fastovsky 1997: #18). 0 0 1 1 1 1 1 1 1 1 1 1 1 2 This character is modifi ed from Parham and Fastovsky (1997) 0 1 1 1 1 0 1 1 1 1 1 1 1 1 so that the derived morphology is restricted to Syllomus and the crown. Argillochelys, Eochelone, and Puppigerus do nonott possess the more distal and triangular lateral process. 22. Coracoid length in relation to humerus: (0) shorter; (1) longer (=Parham and Fastovsky #19).

Data matrix for 31 osteological characters for 13 of the better-known cheloniids cheloniids of the better-known 13 for characters osteological Data matrix 31 for 23. Seventh to eighth centrum articulation of the cervical vertebra: (0) single; (1) doubled. The primitive condition for cheloniids s.l. is a single anterior facet of the seventh Table 1. 1. Table Toxochelys Ctenochelys Euclastes gosseleti Euclastes hutchisoni Argillochelys Eochelone Puppigerus Syllomus Natator Chelonia Eretmochelys Caretta Lepidochelys 30 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003 cervical vertebra (Hirayama 1994). The primitive character state is present in Ctenochelys, Argillochelys, and Euclastes hutchisoni.

Shell 24. Elongated plastron with a broad bridge: (0) absent; (1) present (=Parham and Fastovsky 1997: #20). 25. Rib-free peripherals: (0) only anterior and posterior to ribs; (1) between seventh and eighth ribs; (2) between sixth and seventh ribs (unordered) (=Parham and Fastovsky 1997: #21). Syllomus has thethe derderivedived sstatetate (2). 26. Post nuchal fontanelles: (0) present; (1) absent (=Par- ham and Fastovsky 1997: #22). 27. Additional peripherals (0) absent; (1) present (=Par- ham and Fastovsky 1997: #23). The primitive condition for hard-shelled sea turtles is to have eleven peripherals on each side. 28. Additional pleural scales: (0) absent; (1) present. Primitive cheloniid s.l. taxa have four pleural scales on each side of the shell. Caretta caretta andand Lepidochelys havehave atat leastleast fi ve pleural scales per side (Parham and Fastovsky 1997), and Lepidochelys ccanan hhaveave uupwardspwards ttoo eelevenleven ((DeraniyagalaDeraniyagala 11939).939). The fossil carettine, Procolpochelys, retainsretains thethe primitiveprimitive condi-condi- tion (Zangerl and Turnbull 1955). 29. Neurals (0) between eight and nine; (1) usually ten; (2) variable between extensive neural fragmentation and neural reduction. Fragmentation of the neurals is a com- mon phenomenon among cheloniids, though the degree of fragmentation varies. Toxochelys Ctenochelys, Puppigerus, Argillochelys, andand Eochelone (Zangerl(Zangerl 1953,1953, MoodyMoody 1974)1974) primitively possess eight or nine neurals. Chelonia and Eret- mochelys FFitzingeritzinger 11843843 uusuallysually hhaveave ttenen ((DeraniyagalaDeraniyagala 11939).939). Fig. 9. A summary of 10 equally parsimonious trees discovered Syllomus, Procolpochelys, Natator, and Lepidochelys possess at by phylogenetic analysis. The numbers on either side of the least eleven neurals (Deraniyagala 1939, Zangerl and Turnbull branch correspond to decay indices/bootstrap values (1000 repli- 1955, Weems 1974, Zangerl et al. 1988). Lepidochelys ccanan hhaveave cates) respectively. Taxa are stem based (semi-circle), node based 12 to 15 neurals, while Caretta is polymorphic and can exhibit (open circle). fragmentation or reduction of neurals (Deraniyagala 1939). Natator can havehave up ttoo 1122 neurals (Zang(Zangerlerl et al. 11988).988). 30. Textured carapace elements: (0) absent; (1) present. hypothesis presented here and that presented by Parham and Zangerl et al. (1988) describes an “irregular vermiculation” Fastovsky (1997) are in the relationships of the crown group. on the carapace elements of Natator. Natator, Syllomus, and In our analysis, four of the 10 most parsimonious trees place Argillochelys shareshare tthishis ccharacter.haracter. Syllomus aass tthehe ssisterister ttaxonaxon ttoo Natator, a hhypothesisypothesis ffavoredavored bbyy 31. Shape of pygal: (0) notched posteriorly; (1) not Hirayama (1994). In fi ve of our trees,Chelonia and Eretmo- notched (=Parham and Fastovsky 1997: #24). Upon revisit- chelys aarere ssisterister ttaxa,axa, a hhypothesisypothesis nnotot ssupportedupported bbyy mmolecularolecular ing this character, it was noticed that the pygal is not notched data (Dutton et al. 1996). In all trees, Euclastes hutchisoni is posteriorly for Euclastes gosseleti, andand itit isis trulytruly unknownunknown asas toto the sister taxon of Euclastes gosseleti and nonott near tthehe crcrown.own. whether or not Argillochelys hashas a notchednotched pygal.pygal. Additionally,Additionally, The relatively basal position of Euclastes within Cheloniidae Puppigerus wwasas incorincorrectlyrectly coded in PParhamarham and FFastovskyastovsky s.l. is based on the absence of derived features. Plesiomor- (1997) as having the primitive condition. phic characters retained by Euclastes hutchisoni (and other Euclastes where known) include a wider than long plastron, DISCUSSION a Toxochelys-like-like humerhumerus,us, ffemoralemoral trtrochantersochanters separatseparateded bbyy a deep fossa, a broad sutural contact between the vomer and The results of our cladistic analysis are 10 equally parsi- premaxillae on the palatal surface, and a single facet on the monious trees (53 steps, CI=.66). Figure 9 shows the strict anterior end of the eighth cervical vertebra. These characters consensus of these trees plotted against the stratigraphic oc- leave little doubt that despite its young age, E. hutchisoni is currences of included taxa. The major differences between the not closely related to the crown (Cheloniidae s.s.). LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 31

Because it is known from both cranial and postcranial re- ACKNOWLEDGMENTS mains, Euclastes hutchisoni isis oneone ofof thethe better-knownbetter-known speciesspecies We would like to start by thanking Bob Ernst for access of Euclastes. Two other Euclastes havehave postcranialpostcranial elements to specimens at the Buena Vista Museum and for his noble preserved: (1) the well-preserved skeletons of E. gosseleti ffromrom efforts to preserve the fossils from Sharktooth Hill. SCL es- late Paleocene of Belgium; (2) a highly gyspumized specimen pecially thanks Eduardo Avelar and her family, who provided of Euclastes sp. frfromom tthehe LatLatee CrCretaceousetaceous MorMorenoeno FForma-orma- invaluable support and encouragement throughout the course tion (Foster 1980). In all three instances, the postcrania of of this project. SCL also thanks her mentors Joe Medeiros, Euclastes conformconform toto a levellevel of specialization intermediateintermediate Tricia Maloney, Jenny Davidson, and Karen Haubensak. between the earliest cheloniids s.l. (e.g., Toxochelys) and Kevin Padian of the UCMP is thanked for his unwavering modern Cheloniidae. support of turtle research and helpful comments. Pat Holroyd The young age of E. hutchisoni makesmakes thethe possible pres-pres- was instrumental in helping both authors study materials ence of nasals unexpected. Prior to the tentative recognition at the UCMP, and along with Nick Pyenson and Thomas of these elements in Euclastes hutchisoni, theythey werewere restrictedrestricted Stidham, took part in the 2002 “expedition” to Sharktooth to the basal-most lineages within cheloniids s.l. (Toxochelys Hill. Fellow chelonologists Ted Papenfuss, Chris Feldman, and the Lophochelyinae Zangerl 1953). Nasals are certainly and Thomas Stidham aided JFP in previous visits to the absent in the oldest described specimens of Euclastes (Fas-(Fas- BVM. Mike Metz facilitated some of those early visits. Sam tovsky 1985). Mcleod helped arrange for the loan of the holotype to Kevin The Miocene turtle fauna of Sharktooth Hill can be Padian so that it could be studied by the authors, and also compared to a coeval assemblage from the Atlantic Coast, allowed Jane Mason to skillfully uncover more of the nasal the Calvert Cliffs of Maryland (both are Barstovian). That region. JFP would like to thank Carl Gillies, Kevin Moniz, fauna includes three species, “Psephophorus” calvertensis, Pro- and the Parham family. During the course of this study, colpochelys grandaeva Leidy 1851, and Syllomus aegyptiacus. JFP was funded by the University of California Museum of A dermochelyid close to (potentially conspecifi c with) P“ .”.” Paleontology, a National Science Foundation Graduate Fel- calvertensis existsexists in SharktoothSharktooth Hill, but directdirect comparisonscomparisons lowship, a University of California Vice Chancellor’s Graduate are lacking. Syllomus aegyptiacus is widesprwidespreadead in Miocene Fellowship, an Annie Alexander Fellowship, and grants from oceans, also recorded from Asia (Shikama 1956) and Africa the Sam and Delores Welles fund and Sigma Xi (National (Lydekker 1889b), and so its probable appearance at Shark- Chapter). This is UCMP Contribution #1801. tooth Hill is not surprising. However, we emphasize that the sole specimen of a Syllomus-like-like tturtleurtle ffromrom CCaliforniaalifornia mmayay bbee LITERATURE CITED a different taxon of sculptured cheloniid s.l.. The reciprocal Averianov, A.O., and A.A. Yarkov. 2000. Some turtle remains from absence of Procolpochelys and Euclastes indicatesindicates a differencedifference the Cretaceous and Paleogene of Volgograd region, Russia. Rus- between the two faunas. Procolpochelys is hypothesized to be sian Journal of Herpetology 7(2):161–166.7(2):161–166. a basal carettine (Zangerl and Turnbull 1955), perhaps the Barnes, L.G. 1976. Outline of eastern North Pacifi c fossil cetacean oldest known member of the crown. On the other hand, assemblages. Systematic Zoology 25(4):321–343. Euclastes hutchisoni is the last vestige of a Cretaceous-Paleo- Barnes, L.G. 1978. A review of and and theirtheir cene radiation of basal stem cheloniids. relationships to the delphinoid family Kentriodntidae (: The total range of Euclastes specimens is LatLatee CrCretaceousetaceous Odonotoceti). Natural History Museum of Los Angeles County to the middle Miocene, over 50 million years. The vast ma- Science Bulletin 28:1–35. jority of Euclastes specimensspecimens datedate toto thethe fi rrstst ttenen mmillionillion Barnes, L.G., and E. Mitchell. 1984. Kentriodon obscurus (Kellogg, years of this interval (Late Cretaceous to late Paleocene). 1931), a fossil (Mammalia: ) from the Post-Paleocene Euclastes araree rrestrictedestricted ttoo two far fl ung oc- Miocene Sharktooth Hill bonebed in California. Contributions currences: and (Owen 1842). E. hutchisoni E. planimenta in Sciences of the Los Angeles County Museum 353:1–23. The latter is known from a single skull from the early Eocene Batsch, A.J.G.C. 1788. Versuch einer Anleitung, zur Kenntniß und London Clay. The decline of is concomitant with Euclastes Geschichte der Thiere und Mineralien. I. Akademische Buch- the increased occurrence of more crownward forms, most handlung, Jena. 528 pp. of which are too fragmentary to include in cladistic analyses Berggren, W., and J.A. Van Couvering. 1974. The late . (see Weems 1988; Lapparent de Broin 2001). The last ap- Biostratigraphy, geochronology and paleoclimatology of the pearance of is coeval with the fi rst appearance of Euclastes last 15 million years in marine and continental sequences. and , both of which are hypothesized Procolpochelys Syllomus Palaeogeography, Palaeoclimatology, and Palaeoecology 16(1/2):16(1/2): to be the oldest members of the crown. Continued research i–xi, 1–216. into the morphology and phylogenetics of Cenozoic marine Berry, C.T., and W.G. Lynn. 1936. A new turtle, Peritresius virgin- turtles will undoubtedly shed more light on the moderniza- ianus, fromfrom thethe MioceneMiocene ofof Virginia.Virginia. Proceedings of the American tion of sea turtle faunas. Philosophical Society 76(2):175–190. Bonaparte, C.L. 1832. Saggio d’una distribuzione metodica degli animali vertebrati a sangue freddo. Antonio Boulzaler, Roma. 32 PALEOBIOS, VOL. 23, NUMBER 3, APRIL 2003

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Fig. 10. Distribution of Euclastes (see Appendix 1).

Zangerl, R., and W.D. Turnbull. 1955. Procolpochelys grandaeva Quiriquina Euclastes Gasparini and Biro-Bagoczky (Leidy), an early carettine sea turtle. Fieldiana: Zoology 37:37: (1986). Age—Late Cretaceous (). Locali- 345–382. ty—Quiriquina Formation, Lirquén Province, Chile. Com- Zug, G.R. 2001. Turtles of the Lee Creek mine (: North ments—“Osteopygis ssp.”p.” ooff GGaspariniasparini aandnd BBiro-Bagoczkyiro-Bagoczky Carolina). Smithsonian Contributions to Paleobiology 9 90:0: (1986) and “Osteopygis aff.aff. sculptus” of KarlKarl et al. (1998).(1998). 203–218 The type specimen of Osteopygis sculpsculptustus Staesche 1929 is a pleurodire (de Broin and de la Fuente 1993). APPENDIX I Euclastes priscus (Karl,(Karl, Tichy,Tichy, andand RuschakRuschak 1998).1998). Age— The following is a review of 12 previously published Late Cretaceous (Maastrichtian). Locality—Phosphates of records of Euclastes lislistedted in tthreehree sstratigraphictratigraphic bins (Cr(Cre-e- Morocco, Northwest Africa. Type specimen—IGPS No. taceous, Paleocene, Eocene), in order of publication re- 590, a skull. Comments—“Osteopygoides priscus” o off K Karlarl spectively. All of these records are represented in Fig. 10. et al. (1998). “Euclastes” melii MisuriMisuri 19101910 fromfrom thethe Miocene of ItalyItaly is Paleocene considered to be a carettine (Zangerl and Turnbull 1955, Weems, 1974) and therefore excluded. De Lapparent de Euclastes platyops Cope 11867.867. Age—Late Paleocene. Lo- Broin (2000) records the presence of other Euclastes-like-like cality—Vincentown Formation, Hurffsille, New Jersey, USA. taxa in the Paleogene phosphates of Morocco and Tunisia, Type specimen—ANSP 10187, a skull. Comments—Euclastes but claims that “Euclastes” douvillei De StefanoStefano 11902902 frfromom platyops is thethe type species of Euclastes. Hay (1908) thought the Eocene of Tunisia is not one of them. On the other that the genus Euclastes wwasas prpreoccupiedeoccupied and so ererectedected a hand, “Thalassochelys” phosphatica De StefanoStefano 11903,903, frfromom new genus, Rhetechelys. We are unable to fi nd an additional the same formation, may be a Euclastes. usage of Euclastes anywhere and so follow Kuhn (1964) and de la Fuente and Casadío (2000) in considering Euclastes as Cretaceous the valid genus name for E. platyops. Hornerstown Euclastes Wieland (1904). Age—Late Euclastes gosseleti (Dollo 1886).1886). Age—Late Paleocene. Cretaceous (Maastrichtian; see Staron et al., 2001). Local- Locality—Erquelinne Sands, Belgium. Type specimen— ity—, New Jersey, USA. Com- I.R.Sc.N.B. No. 1563, a nearly complete carapace, partial ments—This turtle includes all of the skull material formerly plastron, good skull and mandible, part of the tail, and part referred to Osteopygis emarginatus. of the pelvis. Comments—This species was originally placed Moreno Euclastes Foster (1980). Age—Late Cretaceous. in the genus Pachyrhynchus Dollo 1886,1886, a name preoccupiedpreoccupied Locality—Moreno Formation, California, USA. Com- by a curculionid beetle (Pachyrhynchus Germar 1824). The ments—“Osteopygis sp.” of Foster (1980). next year Dollo (1887) transferred the species to the genus LYNCH & PARHAM—HARD-SHELLED SEA TURTLESTURTLES 35

Erquelinnesia, and then a year later (Dollo 1888) to Euclastes, Pampaemys de la Fuente and Casadío 2000. the combination employed here. Karpovka Euclastes Averianov and Yarkov (2000). Brightseat Euclastes Weems (1988). Age—Early Paleo- Age—Late Paleocene. Locality—Karpovka Formation, Vol- cene. Locality—Brightseat Formation, Maryland, USA. gograd Region, Russia. Comments—“Osteopyginae indet.” Comments—“Osteopygis emarginatus” of WeemsWeems (1(1988).988). of Averianov and Yarkov (2000). Euclastes roundsi WeemsWeems (1988)(1988) Age—Late Paleocene Oued Zem Euclastes de Lapparent de Broin (2000). (Thanetian). Locality—Piscataway Member of the Aquia For- Age—Late Paleocene to Early Eocene. Locality—Ouled mation, Virginia, USA. Type specimen—USNM 412108, a Abdoun Basin. Comments—According to de Lapparent de partially preserved skull, with only the ventral surface readily Broin (2000), the skulls of these undescribed turtles (“Os- visible. Comments—This turtle was originally called Osteopy- teopygidae indet.”) are often sold attached to the shells of gis roundsi bbyy WWeemseems ((1988)1988) wwhoho aalsolso rrefersefers aadditionaldditional mmate-ate- the pleurodire Cope 1869.1869. rial to this taxon including a costal fragment (USNM 9357), isolated plastral elements (USNM 357710), and carapace Eocene fragments associated with a skull (USNM 357713). These Euclastes planimenta (Owen(Owen 1842).1842). Age—Early Eocene. referrals are considered invalid based on insuffi cient evidence. Locality—London Clay, Harwich region, United Kingdom. The type specimen is a skull and so therefore no postcrania Type specimen—S.M.C. 20419, a skull with jaw attached. can be confi dently referred toE. roundsi. The referred skull Comments—This turtle is the type species of Glossochelys specimen, USNM 357713, is too poorly preserved to be Seeley 1871. referred to E. roundsi withwith confi dence. dence. Euclastes meridionalis (de(de lala FuenteFuente andand CasadíoCasadío Miocene 2000) Age—Early Paleocene. Locality—Roca Formation, Euclastes hutchisoni LynchLynch andand ParhamParham 2003.2003. Age— Cerros Bayos, La Pampa Province, Argentina. Type speci- Middle Miocene. Locality—Sharktooth Hill, Kern County, men—GHUNLPam 19137, a posteromedial skull fragment. California, USA. Type specimen—103351, a skull and jaw. Comments—This taxon was originally placed in its own genus