550 5 GEOLOGY LIBRARY iELDIANA r Geology NEW SERIES, NO. 45 The Cranial Anatomy of Placochelys placodonta Jaekel, 1902, and a Review of the Cyamodontoidea (Reptilia, Placodonta) Olivier Rieppel £J October 31, 2001 Publication 1514 {== CO Z PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY W « LU E B at iuinrbANA-CHAMPAIGN HI rmation for Contributors to Fieldiana QpQLOQYlnfe Generall|Jjk/zvL is primarily a journal for Field Museum staffmembers and research associates, although manusTchreiptJsoufrrnoamlnocanrarfifeisliaatpeadgeaucthhaorrgsemoafy$b6e5.c0o0nspiedrerperdinatsedsppaacgeepeorrmiftrsa.ction thereof. Payment ofat least 50/o of pagechargesqualifiesapaperforexpeditedprocessing, whichreducesthepublicationtime. 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Where abbreviations are dTeLs-i2raTblaexo(neogmicinLictietraattiuonreobfysyF.noAn.ymSiteasf)l,euau&thRo.rsS.coCnsoiwstaennt(ly19s7h6oueltdsefqo.l)lo(wboBtoantiacnailcop-apPeerrsi)odoircSuemr-iHaulntSoiuarncuemsafnodr the Biosis Data Base (1983) published by the BioSciences Information Service. Names ofbotanical authors should followthe"DraftIndexofAuthorAbbreviations, RoyalBotanic Gardens,Kew," 1984edition, or TL-2. References shouldbetypedinthe following form: Croat T B 1978 FloraofBarroColorado Island. StanfordUniversityPress, Stanford, Calif, 943 pp. GLMrauunrbgrbda'onPEaA.JcnmuJdeEar1Rd9iJJ4oc.6rAa.RM'n.I.STLITchln1hheod9weiy7aad9hrnfi.,oszsr.,taeYosneraVtdiodgsclse..tT,rtaurS2cim,pDbti.oeurTsnriPhtegs,eeo,nfptnSAhhiEhenyncasdgSumieitaaoaodongnnonsnar.,o:,CmiaCy1vpnu,9ipld6l.ta3iuSz.nrt7adaat8rAli5fsol-.npoc8sraMo.i2tsom1ttepu.BiracutnslroI.slinneJsitoonPSiunutnrvbeinlowsa1ifai4lsro3hmdno,eo,sfr,nsBEtJ,up.caprTon.Hlehe.oae6,gu3ayH-ne,ao8ddgf50u1.lAe:oHm,Iw5aenlN6nrae7Bdint-rcbdh6oaoe0wrnro1amlk.iaaEnnntodfh,fosnroDeSl.sootugLtyi.h,,n Stolze,SRm.itGh.so1n9i8a1n.IFnsetrintsutiaonnd,Wfaesrnhianlgliteosn,ofD.GCu.atemala. Part II. Polypodiaceae. 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Page Proofs: Fieldiana employs a two-step correction system. The corresponding author will normally receive a copy ofthe edited manuscripton whichdeletions, additions, and changes canbe made andqueries answered. Only oCnheansgeetsofinppaaggeepprrooooffssw(ialslobpepossenetd.tAollcodrerseicrtieodnsc)orarreectvieornyseoxfpetnyspievem.usAutthboer-mgaedneeroantetdhcehsainnggelse isnetpaogfepapgroeofpsrocoafsn. onlybemade iftheauthoragrees inadvancetopay forthem. © This paper meets the requirements otANSI/NISO Z39.48-1992 (Permanence ot Paper). FIELDIANA Geology NEW SERIES, NO. 45 The Cranial Anatomy of Placochelys placodonta Jaekel, 1902, and a Review of the Cyamodontoidea Kept in, Placodonta) < i I Olivier Rieppel DepartmentofGeology FieldMuseum ofNatural History 1400 South Lake Shore Drive Chicago, Illinois 60605-2496 U.S.A. Accepted March 7, 2000 Published October 31, 2001 Publication 1514 PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY © 2001 Field Museum of Natural History ISSN 0096-265 1 PRINTED IN THE UNITED STATES OF AMERICA «-VU/UTUfcfft*ft, no u-r Table of Contents Cyamodus rostratus (Munster, 1839) 76 Placochelyida, new taxon 78 Macroplacus Schubert-Klempnauer, 1975 .. 78 Abstract 1 Macroplacus raeticus Schubert-Klemp- Introduction 1 nauer, 1975 78 Material Included in This Study 2 Unnamed Taxon 78 List of Abbreviations Used in the Figures Protenodontosaurus Pinna, 1990b 78 3 Protenodontosaurus italicus Pinna, 1990b .. 79 The Cranial Anatomy of Placochelyspla- Placochelyidae Romer, 1956 79 codonta 3 Placochelys Jaekel, 1902 79 Measurements of the Holotype 5 Placochelysplacodonta Jaekel, 1902 79 Morphological Description of the Skull 6 Psephoderma Meyer, 1858 85 Morphological Description of the Lower Psephoderma alpinum Meyer, 1858 86 Jaw 21 Placochelys and Potential Turtle Rela- Dermal Ornamentation of the Skull 23 tionships of the Cyamodontoidea 87 Comparison of the Cranial Anatomy of Paleobiogeography and Paleoecology of Placochelysplacodonta with That of Cyamodontoid Placodonts 92 Other Cyamodontoid Placodonts 23 Acknowledgments 95 The Cranial Anatomy of Cyamodus ros- Literature Cited 95 tratus (Minister, 1839) 24 Appendix I 101 The Cranial Anatomy of Cyamodus muensteri (Agassiz, 1839) 33 The Cranial Anatomy of Cyamodus "/a- ticeps" (Owen, 1858) 35 List of Illustrations The Cranial Anatomy of Cyamodus kuhnschnyderi Nosotti and Pinna, 1993a 37 1. Skull of Placochelys placodonta Jaekel The Cranial Anatomy ofCyamodus hilde- (holotype) 4 gardis Peyer, 1931a 39 2. Skull of Placochelys placodonta Jaekel The Cranial Anatomy of Henodus chel- (paratype) 5 yops v. Huene, 1936 39 3. Skull of Placochelys placodonta Jaekel The Cranial Anatomy ofMacroplacus (holotype) 8 raeticus Schubert-Klempnauer, 1975 .. 49 4. Skull of Placochelys placodonta Jaekel The Cranial Anatomy of Protenodonto- (holotype) 10 saurus italicus Pinna, 1990b 56 5. Skull of Placochelys placodonta Jaekel The Cranial Anatomy of Psephoderma (paratype) 12 alpinum H. v. Meyer, 1858 59 6. Braincase of Placochelys placodonta Autapomorphies in the Skull of the Cy- Jaekel (holotype) 14 amodontoidea 63 7. Occiput of Placochelys placodonta Jae- Evolution of the Rostrum and of the Den- kel (paratype) 18 tition Within the Cyamodontoidea 65 8. Occiput of Placochelys placodonta Jae- Cladistic Analysis of Cyamodontoid In- kel (holotype) 19 terrelationships 67 9. Lowerjaw ofPlacochelysplacodonta Systematic Paleontology 71 Jaekel (holotype) 22 Cyamodontoidea Nopcsa, 1923 71 10. Lowerjaw of Cyamodus hildegardis Cyamodontida, new taxon 72 Peyer 23 Henodus Huene, 1936 72 11. Skull of Cyamodus rostratus Munster Henodus chelyops Huene, 1936 72 (holotype) 24 Cyamodontidae Nopcsa, 1923 73 12. Skull of Cyamodus rostratus Munster Cyamodus Meyer, 1863 73 (holotype) 26 Cyamodus hildegardis Peyer, 1931a 73 13. Skull of Cyamodus rostratus Munster Cyamodus kuhnschnyderi Nosotti and (holotype and referred specimen) 28 Pinna, 1993 74 14. Pterygoid of Cyamodus rostratus Mun- Cyamodus muensteri (Agassiz, 1839) 75 ster (referred specimen) 31 in 15. Lowerjaw of Cyamodus rostratus 38. Dermal ossifications referred to IPla- Miinster (referred specimen) 32 cochelys 84 16. Skull of Cyamodus muensteri (holo- 39. Area cladogram for the cyamodontoid type) 33 placodonts 94 17. Skull of Cyamodus muensteri (holotype of C. "laticeps" Owen) 34 18. Skull ofHenodus chelyops v. Huene List of Tables 40 (syntype) 19. Skull of Henodus chelyops v. Huene (syntype and referred specimen) 41 20. Skull of Henodus chelyops v. Huene 1. Measurements of maxillary and pala- (syntypes) 42 tine tooth plates of Placochelysplaco- 21. Skull ofHenodus chelyops v. Huene donta (holotype) 5 (syntype and referred specimen) 44 2. Measurements of the dentary tooth 22. Premaxillary denticles in Henodus plates of Placochelys placodonta (holo- chelyops v. Huene 44 type) 21 23. Right side of dermal palate in Henodus 3. Measurements of the palatine tooth chelyops v. Huene 46 plates of Cyamodus rostratus (holo- 24. Suspension of left quadrate in Henodus type) 29 chelyops v. Huene 47 4. Measurements of the dentary tooth 25. Lowerjaw ofHenodus chelyops v. plates of Cyamodus rostratus (referred Huene 48 specimen) 32 26. Skull ofMacroplacus raeticus Schu- 5. Dentitional characters of species of the bert-Klempnauer (holotype) 50 genus Cyamodus 33 27. Skull of Protenodontosaurus italicus 6. Measurements of the tooth plates of Pinna (holotype) 54 Cyamodus muensteri 37 28. Skull ofPsephoderma alpinum H. v. 7. Proportions of the posterior palatine Meyer 59 tooth plate throughout the Cyamodon- 29. Skull ofPsephoderma alpinum H. v. toidea 39 Meyer 60 8. Skull proportions of cyamodontoid pla- 30. Left lateral braincase wall of Placodus codonts 51 gigas Agassiz 64 9. Measurements of the maxillary and 31. Most parsimonious unrooted network palatine tooth plates ofMacroplacus for Placodontoidea 67 raeticus (holotype) 53 32. Most parsimonious reconstruction of 10. Measurements of the maxillary and 33. paMpllmoaasocctdoouddpsooannrhttsiiliimnndttoeeegnrrairrroeedullisaasttiiriooennncscsohlhniiusppdtsser,ducwtiitohnCoyf- 6689 1121.. psdDMaoaaelnutaatrastuuirsmnreaeelitamtrttaeoiilonxoittcnhufsssohpriol(pfathsthoteelhsoeatonymfapalePxy)irsliosltaeornfyodpaolnnadtcoo-- 5686 34. Strict consensus tree for placodont in- palatine tooth plates ofPlacochelysmal- terrelationships, with the Negev speci- anchinii Boni, 1947 84 men included 71 13. Measurements of the maxillary and 35. Skull of Placochelys alpis sordidae palatine tooth plates of Psephoderma Broili (holotype) 81 alpinum 85 36. Skull of Placochelys alpis sordidae 14. Data matrix for the implementation of Broili (holotype) 81 the Brooks parsimony analysis in the 37. Holotype of Placochelys stoppanii Oss- reconstruction of cyamodontoid histori- wald 83 cal biogeography 85 IV The Cranial Anatomy of Placochelys placodonta Jaekel, 1902, and a Review of the Cyamodontoidea (Reptilia, Placodonta) Olivier Rieppel Abstract The skull of Placochelys placodonta Jaekel is described in detail and compared with all other cyamodontoid skulls kept in public repositories. Cladistic analysis based on a character set derived from cyamodontoid skull anatomy results in a reconstruction of placodont interre- lationships as follows: (Paraplacodus (Placodus ((Henodus, Cyamodus) (Macroplacus (Pro- tenodontosaurus (Placochelys, Psephoderma)))))). The monophyly of the Cyamodontoidea is very robust, supported in particular by a suite of derived braincase characters. On the basis of present evidence, Henodus is the sister taxon of Cyamodus, and the monophyletic genus Cy- amodus includes C. hildegardis. The monophyly of placochelyids, including Placochelys and Psephoderma, is strongly supported also. A detailed comparison of skull anatomy provides no basis for a hypothesis of close phylo- genetic relationships ofturtles and cyamodontoid placodonts. Any similarities between the two clades, particularly with respect to the development of extensive dermal armor, must be con- vergent. The historical paleobiogeography of cyamodontoid placodonts can largely be understood as a sequence of vicariance events that involved an early bifurcation establishing separate clades in the Germanic Basin and on the Eurasian carbonate platform. Subsequent vicariance estab- lished separate clades in the northern Alpine Triassic and in the southern Alps on the Hungarian platform, with further subdivision of the clades within the latter. Introduction mation, upper Bithynian, upper lower Anisian: Druckman, 1974). The latest occurrences of cy- Cyamodontoid placodonts are aclade ofmarine amodontoids are from the Rhaetian of the north- reptiles that occurs in shallow epicontinental and ern (Psephoderma: Meyer, 1858a, b; Broili, 1921; nearshore deposits of Middle and Upper Triassic Macroplacus: Schubert-Klempnauer, 1975) and age throughout the western Tethyan faunal prov- southern (Psephoderma: Osswald, 1930; Boni, ince. The earliest cyamodontoid placodont to ap- 1946 [1947], 1947 [1948]; Pinna, 1975, 1976a, b, & pear in the fossil record is Cyamodus tarnowitz- 1978, 1979; Pinna Nosotti, 1989) Alpine Tri- ensis Giirich, 1884, a skull (now lost) from the assic and from the Rhaetian of England (Meyer, Karchowice Beds of Tarnowskie Gory, Poland 1858a, b; Storrs, 1994; see also Pinna, 1990a). (formerly Tarnowitz in Upper Silesia), which be- Other localities that have yielded cyamodontoid long to the uppermost lower Muschelkalk (lower placodonts are in the Anisian of Transylvania Illyrian, lowerAnisian). Anotherearly occurrence (Jurcsak, 1982; Huza et al., 1987); the upper Mu- is a skull fragment (Brotzen, 1957; Rieppel, Ma- schelkalk and Keuper of southern Germany (Cy- zin, & Tchernov, 1999) of a cyamodontoid from amodus rostratus, Cyamodus muensteri, and Cy- the lower Muschelkalk of Makhtesh Ramon, Ne- amodus "laticeps" from the upper Anisian [Ag- gev, Israel (Middle Member ofthe Gevanim For- assiz, 1833-45; Minister, 1839; Owen, 1858; FIELDIANA: GEOLOGY, N.S., NO. 45, OCTOBER 31, 2001, PP. 1-104 Meyer, 1863J; Cyamodus kuhnschnyderi from the codonta will also be compared in detail with the & lower Ladinian [Nosotti Pinna, 1993a]; Pse- cranial anatomy of all other cyamodontoids for phosaurus suevicus from the upper Ladinian which skull material is available in an effort to [Fraas, 1896]; Henodus chelyops from the Carni- analyze the phylogenetic interrelationships within an [Huene, 1936]) and of the Lorraine, France the Cyamodontoidea. This will provide the nec- (Corroy, 1928; Rieppel & Hagdorn, 1999); the essary framework forthe identification ofthe bas- Ladinian of the southern Alps {Cyamodus hilde- al cyamodontoid skull morphology and the anal- gardis, Peyer, 1931a); the middle Carnian of the ysis ofevolutionary changes ofskull morphology & Tre Venezie area of northeastern Italy (Pinna within this group of fascinating reptiles. Zucchi Stolfa, 1979; DallaVecchia, 1993; Proten- odontosaurus italicus, Pinna, 1990b); the Ladini- an of northeastern Spain (Rieppel and Hagdorn, 1998); and Middle Triassic (?Anisian, Ladinian) Material Included in This Study localities on the northern Gondwanan shelf(Haas, V1i9c5k9e,rs1-9R7i5c;h eGtoracl.e,,1919996)0.; Beltan et al., 1979; The following is a list of material included in Cyamodontoid placodonts were a widespread the present study. Institutional abbreviations are: and taxonomically diverse group characterized by bmnh: British Museum (Natural History), now the development of extensive dermal armor, The Natural History Museum, London; bsp, Bay- which enhanced their chances ofrepresentation in erische Staatssammlung fiir Palaontologie und the fossil record. In its most derived condition, historische Geologie, Munich; fafi, Magayar Al- this dermal armor consisted of a solid carapace, lami Foldtani Intezet (Geological InstituteofHun- linked to a ventral armor by a lateral dermal body gary, Budapest); gpit, Geologisch-Palaontolo- wall (Haas, 1969). This resulted in a remarkably gisches Institut, Universitat Tubingen; HUJ-Pal., turtle-like appearance of cyamodontoid placo- Paleontological Collections, Department of Evo- donts, so much so that, based on his study of the lution, Systematics and Ecology, Hebrew Univer- cranial anatomy and dermal armor ofPlacochelys sity, Jerusalem; mb.r., Museum fiir Naturkunde placodonta, Jaekel (1902a, b, 1907) proposed a der Humboldt Universitat, Berlin, fossil reptile derivation ofturtles from cyamodontoids. The hy- collection; mbsn, Museo Brembano di Scienze pothesis of a relationship of turtles to placodonts Naturali, San Pellegrino; mfsn, Museo Friulano di was later rejected by Gregory (1946), who noted Storia Naturale, Udine; msnb, Museo Civico di that convergent evolution is remarkable in these Scienze Naturali "E. Caffi," Bergamo; msnm, two groups, especially with regard to the dermal Museo Civico di StoriaNaturale di Milano; pimuz, armor. Palaontologisches Institut und Museum der Uni- The more recent finding that turtles may be the versitat Zurich; smf, Senckenberg Museum, sister-group ofSauropterygia among crown-group Frankfurt a.M.; smns, Staatliches MuseumfiirNa- Diapsida (Rieppel & deBraga, 1996; deBraga & turkunde, Stuttgart; st, Museo della Vicaria di S. Rieppel, 1997; Rieppel & Reisz, 1999) has Lorenzio, Zogno (Bergamo, Italy); umo, Urwelt- brought cyamodontoid placodonts back into fo- Museum Oberfranken, Bayreuth. cus. Although a broad-based analysis ofturtle re- Cyamodus hildegardis Peyer, 1931a: pimuz lationships over a wide range of taxa confirmed T4763 (holotype), T4768 (original ofPeyer, 1935, that the similarities shared by turtles and cyamo- PI. 46, Figs, la-c, and Pinna, 1992, Fig. 6), T4771 dontoids are convergent (Rieppel & Reisz, 1999), (original of Pinna, 1992, Fig. 7), T2796 (original a more in-depth analysis of the cranial anatomy of Kuhn-Schnyder, 1959, PI. I, and Pinna, 1992, of cyamodontoid placodonts and its comparison Fig. 8). with that of turtles appears desirable in the at- Cyamodus "laticeps" (Owen, 1858): bmnh R tempt to discover further similarities or differen- 1644 (holotype). ces between the two groups. Placochelys placo- Cyamodus kuhnschnyderi Nosotti and Pinna, donta was selected as primary focus for this pro- 1993a: smns 15855 (holotype), smns 16270 (par- ject not only because Jaekel (1902a, b, 1907) atype); mhi 1294 (incomplete skull). based his hypothesis of a turtle-placodont rela- Cyamodus muensteri (Agassiz, 1839): bsp AS tionship on this taxon, but also because it repre- VII 1210 (holotype, original of Minister, 1830, sents one of the best-preserved cyamodontoid skull no. II; Meyer, 1863, PI. 31, Figs. 1-2). skulls. The cranial anatomy of Placochelys pla- Cyamodus rostratus (Munster, 1839): umo BT FIELDIANA: GEOLOGY