50.5 1 GtOL06Y LIBRARY ,s. _____________^^ 0.36 FIELDIANA Geology NEW SERIES, NO. 36 Revision of the Sauropterygian Reptile Genus Cymatosaurus v. Fritsch, 1894, and the Relationships of Germanosaurus Nopcsa, 1928, from the Middle Triassic of Europe Olivier Rieppel March 31, 1997 Publication 1484 PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY Information for Contributors to Fieldiana General: Fieldiana is primarily a journal for Field Museum staff members and research associates, although manuscripts from nonaffiliated authors may be considered as space permits. The Journal carries a page charge of $65.00 per printed page or fraction thereof. Payment of at least 50% of page charges qualifies a paper for expedited processing, which reduces the publication time. 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Changes in page proofs (as opposed to corrections) are very expensive. Author-generated changes in page proofs can only be made if the author agrees in advance to pay for them. © This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). iJNOIS LIBRA* URBANA.CHAMPA FIELDIANA Geology NEW SERIES, NO. 36 Revision of the Sauropterygian Reptile Genus Cymatosaurus v. Fritsch, 1894, and the Relationships of Germanosaurus Nopcsa, 1928, from the Middle Triassic of Europe Olivier Rieppel Department of Geology Field Museum of Natural History Roosevelt Road at Lake Shore Drive Chicago, Illinois 60605-2496 U.S. A. Accepted June 28, 1996 Published March 31, 1997 Publication 1484 PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY © 1997 Field Museum of Natural History ISSN 0096-2651 PRINTED IN THE UNITED STATES OF AMERICA o^ Table of Contents GE0L06Y LIBRARY Abstract 1 zusammenfassung 1 Introduction 1 Systematic Paleontology 3 Cymatosauridae Huene, 1948 3 Cymatosaurus v. Fritsch, 1894 3 Cymatosaurus fridericianus v. Fritsch, 1894 4 Morphological Description 4 Cymatosaurus latifrons (Gurich, 1884) 6 Morphological Description 10 Cymatosaurus multidentatus (Fv. Huene, 1958) 14 Cymatosaurus sp. ("C. erythreus" E.v. Huene, 1944) 14 Nothosauridae Baur, 1889 15 Germanosaurus Nopcsa, 1928 15 Germanosaurus sp. ("G. latissimus" [Gurich, 1884]) 16 Germanosaurus schqfferi (Arthaber, 1924) 18 Morphological Description 18 Cladistic Analysis 22 Phylogenetic Pattern and Stratigraphic Superposition 29 Acknowledgments 33 Literature Cited 33 Appendix 35 3. Fragmentary skull referred to Cymato- saurus fridericianus 8 4. Snout fragment referred to Cymatosau- rus cf . C fridericianus 8 5. The neotype of Cymatosaurus latifrons (Gurich, 1884) 10 6. The neotype of Cymatosaurus latifrons (Gurich, 1884) 11 7. The holotype of Cymatosaurus ery- threus E.v. Huene, 1894 12 8. The holotype of Cymatosaurus ery- threus E.v. Huene, 1894 13 9. Isolated parietal referred to Cymatosau- rus erythreus E.v. Huene, 1894 15 10. The holotype of Germanosaurus schqf- feri (Arthaber, 1924) 17 1 1 . The holotype of Germanosaurus schqf- feri (Arthaber, 1924) 18 12. Isolated parietal referred to Germano- saurus schqfferi (Arthaber, 1924) 18 13. Phylogenetic interrelationships of the Sauropterygia 19 14. Phylogenetic interrelationships of the Reptilia 19 15. Clade rank determination in Sauropter- ygia 20 16. Clade versus age rank in Sauropterygia .. 20 List of Tables List of Illustrations 1 . The holotype of Cymatosaurus frideri- cianus v. Fritsch, 1894 2. The holotype of Cymatosaurus frideri- cianus v. Fritsch, 1894 Skull proportions in Cymatosaurus, Ger- manosaurus, and Nothosaurus 9 Data matrix for the cladistic analysis of all Cymatosaurus species 18 Data matrix for the cladistic analysis of sauropterygian interrelationships 21 UBRARYU. OF!. UHBANA-CHAMPAIGN Revision of the Sauropterygian Reptile Genus Cymatosaurus v. Fritsch, 1894, and the Relationships of Germanosaurus Nopcsa, 1928, from the Middle Triassic of Europe Olivier Rieppel Abstract Three species are currently recognized within the genus Cymatosaurus from the late Scythian and early Anisian of Europe, viz. Cymatosaurus fridericianus v. Fritsch, 1894, Cymatosaurus latifrons Giirich, 1884, and Cymatosaurus multidentatus (F.v. Huene, 1958). All other previ- ously described species of Cymatosaurus are considered either junior synonyms of Cymato- saurus latifrons (C. gracilis Schrammen, 1899; C. silesiacus Schrammen, 1899) or a nomen dubium (C. erythreus E.v. Huene, 1944). Germanosaurus schqfferi Arthaber, 1924, is recog- nized as a separate genus and species within the Nothosauridae, sister-group of the Notho- saurinae (including Nothosaurus and the Silvestrosaurus-Ceresiosaurus-Lariosaurus clade). Germanosaurus (JEurysaurus) latissimus (Giirich, 1891) is treated as a nomen dubium. A cla- distic analysis based on the critical revision of the genera Cymatosaurus and Germanosaurus improves resolution among Triassic stem-group Eosauropterygia. The resulting cladogram is used as the basis for a comparison of phylogenetic pattern and stratigraphic distribution of the Sauropterygia. Zusammenfassung Innerhalb der Gattung Cymatosaurus aus dem obersten Skyth und unteren Anis Europas werden gegenwartig drei Arten als giiltig anerkannt: Cymatosaurus fridericianus v. Fritsch, 1894, Cymatosaurus latifrons Giirich, 1884, und Cymatosaurus multidentatus (F.v. Huene, 1958). Alle anderen beschriebenen Arten von Cymatosaurus sind entweder jungere Synonyme von Cymatosaurus latifrons (C. gracilis Schrammen, 1899; C. silesiacus Schrammen, 1899) oder ein nomen dubium (C. erythreus E.v. Huene, 1944). Germanosaurus schqfferi Arthaber, 1924, wird als selbtandige Gattung und Art innerhalb der Nothosauridae anerkannt, die die Schwestergruppe der Nothosaurinae (Nothosaurus, "Silvestrosaurus," "Ceresiosaurus," und Lariosaurus) reprasentiert. Germanosaurus (Eurysaurus) latissimus (Giirich, 1891) ist ein no- men dubium. Eine kladistische Analyse, die auf der kritischen Revision der Gattungen Cy- matosaurus and Germanosaurus fusst, resultiert in einem besseren Verstandnis der Verwandt- schaftsverhaltnisse unter triassischen Eosauropterygiern. Auf der Grundlage dieser Analyse wird das Muster der Verwandtschaftsbeziehungen mit dem Muster der stratigraphischen Ver- breitung der Sauropterygia verglichen und diskutiert. Introduction tened skull (and an isolated snout fragment) col- lected in the lowermost Muschelkalk (mu,, lower The genus Cymatosaurus was erected by Anisian) exposed in the quarries of the "Portland- Fritsch (1894) for an isolated, dorsoventrally flat- Cement-Fabrik" at Halle/Saale, Germany. Fritsch FIELDIANA: GEOLOGY, N.S., NO. 36, MARCH 31, 1997, PP. 1-38 1 (1894) recognized many similarities that the spec- imen shares with Nothosaurus, but it differs from the latter genus in having strongly reduced nasals, a trait that Cymatosaurus shares with Pistosaurus from the upper Muschelkalk (mo,) of Bayreuth (Bavaria). Sauropterygia of equivalent or slightly older age (mu,, lowermost Muschelkalk) had previously been collected in the Gogolin beds of Upper Si- lesia, and isolated skulls from those deposits had been described as Nothosaurus latifrons Gurich, 1884, ox Nothosaurus latissimus Gurich, 1891, re- spectively. Fritsch (1894) did not refer to Gurich's (1884, 1891) material, although in his review of the genus Nothosaurus Koken (1893) had sug- gested that Gurich's (1891) species might be re- ferred to a different genus. Schrammen (1899) re- viewed the nothosaurs from the lower Muschel- kalk of Upper Silesia, referred both of Gurich's species to the genus Cymatosaurus, and described two new species, viz. Cymatosaurus gracilis and C silesiacus. Morphological comparison led him to conclude that Cymatosaurus must be close to the common ancestor of Nothosaurus and Pisto- saurus. Freeh (1903) erected the new subgenus Eury- saurus to include Cymatosaurus latissimus, which he found to be intermediate between Cymatosau- rus and Nothosaurus: the frontals are paired and the nasals reduced in Eurysaurus latissimus as in Cymatosaurus, but the reduced nasals still reach the posterior margin of the external naris as in Nothosaurus. Nopcsa (1928a, p. 21, 1928b, p. 173) replaced the genus name Eurysaurus by Ger- manosaurus because the first name was preoccu- pied. This had escaped Arthaber (1924), who in his review of nothosaurs retained Eurysaurus as a subgenus of Cymatosaurus and described a new species, Eurysaurus schafferi, from the lowermost Muschelkalk (mu,, Gogolin beds) of Gogolin, Up- per Silesia. The genus Cymatosaurus was comprehensively reviewed by E.v. Huene (1944), who described another species, Cymatosaurus erythreus, from the upper Buntsandstein (so2, Rot) of Rudersdorf near Berlin, the earliest representative of its genus in the Germanic Triassic. E.v. Huene (1944) re- tained Germanosaurus as a subgenus, to which she referred the species gracilis Schrammen, la- tissimus Gurich, schafferi Arthaber, and silesiacus Schrammen; Cymatosaurus ss. would include the species erythreus E.v. Huene, fridericianus Fritsch, and latifrons Gurich. Jaekel (1911, p. 148, Fig. 161; this specimen can no longer be located today) figured a skull from the lower Muschelkalk of Muhlhausen (Thu- ringia), which he referred to "Nothosaurus (Cy- matosaurus) cf. fridericianus." This skull is clear- ly that of Nothosaurus marchicus (Rieppel & Wild, 1996), as is indicated by its proportions (rel- atively short rostrum, relatively small upper tem- poral fossae, maxillary tooth row not extending up to the midpoint of the upper temporal fossa), the well-developed nasals, the fused frontals, and the relatively forward position of the pineal fo- ramen (see also Schroder, 1914, p. 73). Huene (1958) described a new species of the pachypleurosaur genus Anarosaurus Dames, 1890, from the lower Anisian of the Lechtaler Alps (Austria), Anarosaurus multidentatus. Re- description of the holotype resulted in its identi- fication as Cymatosaurus (Rieppel, 1995c), indi- cating that the genus had expanded from the Mu- schelkalk Basin and reached the Alpine Triassic during early Anisian times (Rieppel & Hagdorn, 1996). Throughout the Germanic and Alpine Tri- assic, the genus Cymatosaurus remains restricted to the lower Muschelkalk and lower Anisian re- spectively. Productive deposits {orbicularis beds, basal middle Muschelkalk) of Esperstadt, Jena, Querfurt, and Rudersdorf have yielded abundant material of Nothosaurus (Rieppel & Wild, 1996), but not a single diagnostic skull fragment of Cy- matosaurus. Analysis of the invertebrate fauna from lower Muschelkalk deposits in the eastern part of the Germanic Basin shows strong Asiatic affinities and indicates that these taxa reached the Muschel- kalk Basin from the Paleotethys through the East Carpathian gate (Kozur, 1974; Hagdorn, 1985; Urlichs & Mundlos, 1985). In view of this paleo- biogeographical context, it is interesting to note that the only possible Cymatosaurus described from outside Europe is Micronothosaurus sten- sioei Haas, 1963, from the upper Muschelkalk of Wadi Ramon, Israel. The specimen differs from Nothosaurus in a number of characteristics, such as the relatively forward position of the pineal foramen, the distinct posterolateral lappets of the frontal approaching the pineal foramen, a narrow postorbital bridge, relatively small upper temporal fenestrae compared to the size of the orbits, no evidence for a posterior extension of the tooth row beyond the posterior margin of the orbit, and a poorly ossified occiput with large posterior open- ings for the cranioquadrate passage. Unfortunate- ly, some morphological details remain obscure in Haas's (1963) description, such as the paired or FIELDIANA: GEOLOGY unpaired condition of the frontal and the relations of the jugal and postorbital along the posterior margin of the orbit. In view of the many shared similarities, Schultze (1970) identified Microno- thosaurus stensioei as a cymatosauroid, possibly even belonging to the genus Cymatosaurus. If this identification is valid, and if Haas's (1963) indi- cation of its stratigraphic occurrence in the upper Muschelkalk is correct, the specimen would sig- nificantly expand the geological occurrence of the genus Cymatosaurus beyond the central and west- ern European occurrences into the uppermost An- isian or lower Ladinian. In fact, Haas (1963, p. 161) specifies that the specimen came from "Brotzen's layer D2 (Cera- tites beds)," but "Nothosaurus or related genera" are cited by Brotzen (1957, p. 202) as coming from the Ceratites zone Dl. The overlying Cer- atites zone D2 was correlated by Brotzen (1957) with the Trinodosus zone, and both zones (Dl and D2) were considered equivalent to the Alpine up- per Anisian (Brotzen, 1957, p. 206). More recent analyses equate the Trinodosus zone of the Teth- yan province with the lower Illyr, of lower upper Anisian age, which corresponds to the upper low- er Muschelkalk (mu2) (Rieber, 1973; Bucher, 1988; Budurov et al., 1993; Brack & Rieber, 1993). Although geologically younger than the occurrence of Cymatosaurus in the Gogolin beds of Upper Silesia, the Israel cymatosauroid still is in deposits equivalent to the lower Muschelkalk. Institutional abbreviations are as follows: bgr, Bundesanstalt fur Geowissenschaften und Roh- stoffe, Berlin; Ha, Institut fur Geowissenschaften, Martin-Luther-Universitat, Halle/Saale; Mbg, Fachbereich Geowissenschaften, Philipps Univer- sitat, Marburg/Lahn; nhmw, Naturhistorisches Museum, Wien; smns, Staatliches Museum fur Naturkunde, Stuttgart. Systematic Paleontology Sauropterygia Owen, 1860 Eosauropterygia Rieppel, 1994a Cymatosauridae Huene, 1948 Definition — A monophyletic taxon including the genus Cymatosaurus. Diagnosis — Small to large eosauropterygians with a moderately depressed skull; snout con- stricted; postorbital skull distinctly elongated; oc- ciput deeply concave; supraoccipital vertically oriented and in loose connection with the der- matocranium; distinctly reduced nasals that may or may not enter the external naris; frontals paired; posterolateral processes of frontals closely approach upper temporal fossa and may enter its anteromedial margin; parietals incompletely or completely fused; jugal enters posterior margin of the orbit and remains excluded from upper tem- poral arch; quadratojugal absent. Distribution — Uppermost Buntsandstein and lower Muschelkalk, lower Anisian, Middle Tri- assic, Europe and ?Israel. Comments — The cladistic analysis discussed below indicates a sister-group relationship of Cy- matosaurus and Pistosaurus, with Corosaurus representing the sister-taxon of the former two. An argument could therefore be made that the lat- ter two genera be included in the Cymatosauridae. This conclusion is not formalized here, because the addition of plesiosaurs and pliosaurs to the analysis may show Pistosaurus to be the sister- taxon of plesio- and pliosaurs (see Sues, 1987; Storrs, 1991, 1993b). The results reported here support the concept of the Pistosauria proposed by Edinger (1935; see also Sanz, 1983; Alafont & Sanz, 1996), to include Cymatosaurus, Pistosau- rus, and, by extension, plesio- and pliosaurs. The Pistosauria may have to be extended to include Corosaurus, or a new higher taxon may have to be named to include Corosaurus and the Pisto- sauria. Cymatosaurus v. Fritsch, 1894 1884 Nothosaurus, Gurich, p. 132, PI. II, Figs. 2-4 1891 Nothosaurus, Gurich, p. 967, Fig. on p. 968. 1894 Cymatosaurus, v. Fritsch, p. 10 1903 Eurysaurus, Freeh, p. 15. 1928a Cymatosaurus, Nopcsa, p. 44 1928b Cymatosaurus, Nopcsa, p. 173. 1944 Cymatosaurus {Germanosaurus) (par- tim), E.v. Huene, p. 208. Type Species — Cymatosaurus fridericianus v. Fritsch, 1894, from the lower Muschelkalk (lower Middle Triassic), Halle/Saale, Germany. Definition — A monophyletic taxon including the species fridericianus, latifrons, and multiden- tatus. RIEPPEL: REVISION OF CYMATOSAURUS Diagnosis — Same as for family, of which this is the only genus. Distribution — Same as for family, of which this is the only genus. Comments — Lamprosauroides goepperti (Mey- er, 1860; Lamprosauroides replaces Lamprosau- rus: K. P. Schmidt, 1927, p. 58) was considered a cymatosauroid by Schrammen (1899, p. 408). In view of its fragmentary nature, Lamprosauroides goepperti (Meyer, 1 860) remains a nomen dubium (Rieppel, 1995a). Cymatosaurus fridericianus v. Fritsch, 1894 1 894 Cymatosaurus fridericianus, v. Fritsch, p. 281 #, PL 16, Fig. 1; PL 17, PL 18, Figs. 1-12. 1899 Cymatosaurus fridericianus, Schram- men, p. 389 j/, PL 24, Figs. 5a-c. 1914 Cymatosaurus fridericianus, Schroder, p. ISjf., Figs. 15, 21. 1924 Cymatosaurus fridericianus, Arthaber, p. 475, Figs. lOa-b. 1928 Cymatosaurus fridericianus, Schmidt, p. 393, Fig. 1105. 1934 Cymatosaurus fridericianus, Kuhn, p. 42. 1944 Cymatosaurus fridericianus, E.v. Hu- ene, pp. 198/ 207/ 1964 Cymatosaurus fridericianus, Kuhn, p. 12 1983 Cymatosaurus fridericianus, Sanz, Fig. lb. 1995c Cymatosaurus fridericianus, Rieppel, p. 295, Figs. 8A-B. Holotype — Skull (Ha, uncatalogued; Figs. 1, 2). Locus Typicus — Lower Muschelkalk (mu,), Halle/Saale, Germany. Diagnosis — A species of Cymatosaurus of large size (tip of snout to back end of parietal skull table up to 200 mm); three maxillary teeth preceding paired maxillary fangs; nasals reduced, excluded from external naris; prefrontal and post- frontal in contact at dorsal margin of orbit; frontal enters anterior margin of upper temporal fossa. Distribution — Lower Muschelkalk (lower An- isian, lower Middle Triassic), central Europe. Referred Specimens — bgr S 44/3: a small and incomplete skull from the lower Muschelkalk (Gogolin Beds, mu,) of Gogolin, Upper Silesia Rieppel, 1994a, Fig. 39). The fragment repre- sents the posterior part of the dermatocranium, from which most of the braincase has dropped out (Fig. 3). This indicates incomplete ossification and hence possibly a juvenile status of the spec- imen (but see further discussion below). The fron- tal enters the anteromedial margin of the upper temporal fossa, a derived feature shared with the holotype of Cymatosaurus fridericianus. The specimen is therefore interpreted as a juvenile representative of the latter species. The snout fragment from the lower Muschel- kalk of Halle referred to Cymatosaurus sp. by Fritsch (1894, p. 300, PL 16, Fig. 2) is not diag- nostic at the species level but differs from Cy- matosaurus fridericianus only by its somewhat smaller size. The specimen can no longer be lo- cated today. A similar snout fragment (smns 7209; Fig. 4) is known from the lower Muschelkalk (mu,) of Freudenstadt. Morphological Description — C. fridericianus is characterized by a relatively long and slender skull with a pronounced rostrum (Fig. 2). The oc- cipital condyle is not preserved. Skull length from the tip of the snout to the posterior end of the parietal skull table is 195 mm, the length from the tip of the snout to the mandibular condyle of the quadrate approximately 238 mm. The occiput is deeply excavated, the mandibular articulations lo- cated well behind the assumed level of the occip- ital condyle. The external nares are almost twice as long as they are broad, and the upper temporal fossa is relatively somewhat smaller than in No- thosaurus. Dividing the distance from the tip of the snout to the anterior margin of the external naris by the width of the skull at the rostral con- striction yields a value of 1.64 (1.2-2.5 in Notho- saurus). Dividing the distance from the tip of the snout to the anterior margin of the orbit by the distance from the tip of the snout to the anterior margin of the external naris results in an index of 1.87 (1.5-2.0 in Nothosaurus). Dividing the dis- tance from the tip of the snout to the anterior mar- gin of the upper temporal fenestra by the distance from the tip of the snout to the anterior margin of the external nares yields a ratio of 2.68 (2.3-3.4 in Nothosaurus). Dividing the longitudinal diam- eter of the external naris by its transverse diameter yields a ratio of 1 .94 (the corresponding ratio var- ies from 1.0 to 2.2 in Nothosaurus, depending on the species). Dividing the longitudinal diameter of the upper temporal fossa by the longitudinal di- ameter of the orbit yields values of 1 .76 (left side) and 1.96 (right side), respectively (the corre- sponding ratio varies from 2.1 to 3.9 in Notho- FIELDIANA: GEOLOGY saurus, with N. marchicus at the lower end and N. mirabilis at the upper end of that range). The relatively long and slender rostrum, formed by the paired premaxillae, is distinctly set off from the bulging maxillaries by a rostral constric- tion. The premaxillary-maxillary suture is located at the anterolateral corner of the external naris. Broad posterior (nasal) processes of the premax- illa separate the external nares from one another and meet the paired frontals in an interdigitating suture at the level of the anterior margin of the orbit. Between the external nares and the orbits, the maxilla is broadened to accommodate the roots of the paired maxillary fangs. The nasals are small, splint-like bones whose posterior tip reach- es the level of the anterior margin of the orbit, but which remain excluded from the posterior margin of the external naris. The lacrimal is lacking. The prefrontal is relatively larger than in Nothosaurus, located at the anterodorsal corner of the orbit, and it meets the postfrontal along the dorsal margin of the orbit. The postfrontal is a large element defining the posterodorsal margin of the orbit as well as the anterior margin of the upper temporal fossa. The postorbital bridge is relatively narrower than in Nothosaurus. Dividing the width of the postorbital bridge by the width of the maxilla be- tween the external naris and the anterior margin of the orbit yields a value of 0.36 for C. frideri- cianus; the corresponding ratio varies from 0.8 to 1 .8 in Nothosaurus (depending on the species). The frontals are large, paired elements that meet the fused parietal at a level somewhat behind the anterior margin of the upper temporal fossa. Unlike any specimens of Nothosaurus (and some skulls of Cymatosaurus [see below]), the frontal enters the anteromedial margin of the upper tem- poral fossa. The parietal is a narrow element with the pineal foramen located slightly anterior to its midpoint. The suture between squamosal and pa- rietal at the posterior margin of the upper tem- poral fossa cannot be identified unequivocally. The squamosal meets the postorbital in an over- lapping suture within the upper temporal arch; the anterior tip of the squamosal lies behind the level of the anterior margin of the upper temporal fossa. The precise shape and relations of the jugal bone, located at the posteroventral margin of the orbit, cannot be identified. It did not, however, extend into the upper temporal arch, approaching the an- terior tip of the squamosal. The ventral view of the skull discloses a large fontanelle between the premaxillae, enlarged by separation of the premaxillae due to dorsoventral compression of the skull. The premaxillary ros- trum carries five tooth positions on each side; re- placement pits are distinctly elongated and drop- shaped, located posteromedial to the functional tooth positions. Three small maxillary teeth pre- cede the paired maxillary fangs. The total count of maxillary teeth cannot be established. The vo- mers are paired elements that meet the maxillae at the anterior margin of the internal nares, thus excluding the premaxillae from the latter. The posterior margin of the internal nares is defined by the palatines. The internal nares are relatively broad and short: division of their longitudinal di- ameter by their transverse diameter yields a ratio of 2.1; corresponding values vary from 1.28 to 3.86 in Nothosaurus, with N marchicus at the lower end and N mirabilis at the upper end of that range. As compared to Nothosaurus, the in- ternal nares are positioned somewhat farther back relative to the external nares (Table 1). The vomers meet the anterior tips of the pter- ygoids in a transversely oriented interdigitating suture behind the level of the posterior margins of the internal naris. The ectopterygoid is a rela- tively short and broad element located at the an- terior margin of the subtemporal fossa, and it forms a well-developed (ecto-)pterygoid flange for the origin of the superficial pterygoideus mus- cle. The quadrate ramus of the pterygoid is well preserved on the right side of the skull and (as in Nothosaurus) shows well-developed flanges at both its medial and lateral edges for the origin of the deep pterygoideus muscle. Discussion — Among all described species of Cymatosaurus, the frontal approaches the antero- medial margin of the upper temporal fossa to a variable degree. Only in Cymatosaurus friderici- anus does the frontal enter the upper temporal fos- sa and participate in the formation of the ventrally descending flange from which originate deep fi- bers of the jaw adductor muscles. Unlike in Cy- matosaurus latifrons, three (rather than one) small maxillary teeth precede the maxillary fangs — the plesiomorphic condition compared to the out- group (Nothosauridae: Rieppel, 1994b). The de- gree of reduction of the nasals (entering external nares or excluded therefrom), as well as the pres- ence or absence of a contact between prefrontal and postfrontal along the dorsal margin of the or- bit, is highly variable among all the specimens of Cymatosaurus ever described, and these charac- ters cannot be used to differentiate separate spe- cies within the genus. RIEPPEL: REVISION OF CYMATOSAURUS Fig. 1. The skull of the holotype of Cymatosaurus fridericianus v. Fritsch, 1894 (Ha, uncatalogued), from the lower Muschelkalk of Halle/Saale. A, Dorsal view; B, ventral view. Scale bar = 20 mm. Cymatosaurus latifrons (Gurich, 1884) 1884 Nothosaurus latifrons, Gurich, p. 132, PI. 2, Figs. 3-4. 1893 Nothosaurus latifrons, Koken, p. 366 ff., Figs. 4-5. 1899 Cymatosaurus (Nothosaurus) latifrons, Schrammen, p. 388/ 1899 1899 1903 1903 Cymatosaurus gracilis, Schrammen, p. 402, PI. 23, Figs. 2-3; PL 25, Figs. 6a- b, 7. Cymatosaurus silesiacus, Schrammen, p. 402, PL 21, PL 22, Figs. 1-2; PL 25. Figs. 3a-e; PL 26, Figs. 1-3. Cymatosaurus gracilis, Freeh, p. 15. Cymatosaurus latifrons, Freeh, Figs. 2a-c. FIELDIANA: GEOLOGY Fig. 2. The skull of the holotype of Cymatosaurus fridericianus v. Fritsch, 1894 (Ha, uncatalogued), from the lower Muschelkalk of Halle/Saale. A, Dorsal view; B, ventral view. Scale bar = 20 mm. Abbreviations: ec, ecto- pterygoid; f, frontal; m, maxilla; n, nasal; p, parietal; pi, palatine; pm, premaxilla; po, postorbital; pof, postfrontal; prf, prefrontal; pt, pterygoid; sq, squamosal; v, vomer. 1903 Cymatosaurus silesiacus, Freeh, p. 15. 1928 1914 Cymatosaurus gracilis, Schroder, p. 78 ff., Fig. 16. 1934 1914 Cymatosaurus latifrons, Schroder, p. 86 1934 ff 1914 Cymatosaurus silesiacus, Schroder, p. 1934 82 ff 1935 1924 Nothosaurus latifrous, Arthaber, p. 476. 1924 Eurysaurus latifrous, Arthaber, p. 477. 1944 1924 Cymatosaurus silesiacus, Arthaber, p. 473. 1944 1928 Cymatosaurus (?) gracilis, Schmidt, p. 394, Fig. 1107. 1944 1928 Cymatosaurus latifrons, Schmidt, p. 394, Fig. 1108. 1964 Cymatosaurus silesiacus, Schmidt, p. 394, Figs. 1106a-b. Cymatosaurus gracilis, Kuhn. p. 43. "Nothosaurus" latifrons, Kuhn, p. 34. Cymatosaurus silesiacus, Kuhn, p. 42. Cymatosaurus silesiacus, Edinger, Fig. 9c. Cymatosaurus gracilis, E.v. Huene, pp. 198/, 208. Cymatosaurus latifrons, E.v. Huene, pp. 198/, 207/ Cymatosaurus silesiacus, E.v. Huene, pp. 198/, 208. Cymatosaurus gracilis, Kuhn, p. 12. RIEPPEL: REVISION OF CYMATOSAURUS Fig. 3. A fragmentary skull (bgr S 44/3) from the lower Muschelkalk of Gogolin, Upper Silesia, referred to Cymatosaurus fridericianus v. Fritsch, 1 894. A, Dor- sal view; B, occipital view. Scale bar = 20 mm. Abbre- viations: bo, basioccipital; f, frontal; p, parietal; po, post- orbital; pof, postfrontal; pt, pterygoid; q, quadrate; sq, squamosal. 1964 Nothosaurus {7 Cymatosaurus) latifrons, Kuhn, p. 8. 1964 Cymatosaurus silesiacus, Kuhn, p. 13. Neotype — The skull described by Gurich (1884) and figured by Freeh (1903, Figs. 2a-c) can no longer be located in public repositories. Schrammen's (1899) second specimen of Cyma- tosaurus "gracilis" (smns 10109; Figs. 5-6) is the only complete skull of Cymatosaurus latifrons available today and is here designated the neo- type. Fig. 4. A snout fragment of Cymatosaurus cf. C. fridericianus (smns 7209) from the lower Muschelkalk of Freudstadt. Scale bar = 20 mm. Locus Typicus — Lower Muschelkalk (Gogolin beds, mu,), Gogolin, Upper Silesia (Poland); for the neotype: lower Muschelkalk (Gogolin beds, mu,), Krappitz (Krapkowice), Upper Silesia (Po- land). Diagnosis — A species of Cymatosaurus of in- termediate size1 (tip of snout to back end of partial skull table up to 150 mm); single maxillary tooth preceding paired maxillary fangs; pre- and post- frontal may or may not be in contact at dorsal margin of orbit; frontal may closely approach but does not enter anteromedial margin of upper tem- poral fossa. Distribution — Lower Muschelkalk (lower An- isian, lower Middle Triassic), central Europe. Referred Specimens — bgr S 44/3 (complete but poorly preserved skull, lower Muschelkalk [lower Gogolin beds], Sacrau near Gogolin; smns 10977 (incomplete skull, uppermost Buntsand- stein [Coelestinschichten, uppermost Rot], Jenzig near Jena [Rieppel, 1994b, Fig. 11]). Comments — The original (type) material of Cy- matosaurus latifrons (Gurich, 1 884) can no longer be located today. Freeh (1903) figured the speci- men after additional preparation, but unfortunate- ly published the photograph with retouched suture lines. Following Freeh's (1903) interpretation, the nasals remain excluded from the posterior margin of the external nares, as in Cymatosaurus frider- 1 A small and as yet undescribed species of Cymato- saurus from the lower Muschelkalk of Thuringia differs from other species of its genus by relatively long and narrow upper temporal fenestrae and the presence of a sagittal crest. The species will be described elsewhere in collaboration with R. Werneburg, Natural History Mu- seum Schleusingen. FIELDIANA: GEOLOGY Table 1. Skull proportions in Cymatosaurus, Ger- manosaurus, and Nothosaurus. 0 I e s <* I e I M 1 I S snout - orbit snout - external naris 1.9 - 2.0 1.8 1.6-2.0 snout - temporal fossa snout - external naris 2.7 - 3.0 2.86 2.3 - 3.4 long. 0 temporal fossa long. 0 orbit 1.3 - 2.0 1.87 2.1-3.9 snout - internal nares snout - external nares 1.2 - 1.43 1.33 1.04-1.16 icianus and in Schrammen's (1899) "second" specimen (see below for details of Schrammen's original material) of Cymatosaurus gracilis. The frontals appear to closely approach the antero- medial margin of the upper temporal fossa, but they remain excluded from them. Prefrontal and postfrontal are in contact at the dorsal margin of the upper temporal fossa, as in Cymatosaurus fri- dericianus, in Schrammen's (1899) "first" speci- men of Cymatosaurus silesiacus, and in Schram- men's (1899) "second" specimen of Cymatosau- rus gracilis; in Schrammen's (1899) "first" spec- imen of Cymatosaurus gracilis, prefrontal and postfrontal remain separated at the dorsal margin of the orbit. In the (lost) holotype of Cymatosau- rus latifrons, the width of the dorsal bridge be- tween the orbits (12 mm) is 1.7 times the width of the dorsal bridge between the external nares (7 mm), and the distance from the external naris to the orbit is approximately 2.8 times the width of the postorbital arch. With these values, the (lost) holotype of Cymatosaurus latifrons combines val- ues otherwise typical for Cymatosaurus gracilis and Cymatosaurus silesiacus. Schrammen (1899) described Cymatosaurus gracilis on the basis of two specimens, one an incomplete skull exposed in dorsal view (Schram- men's [1899, PI. 23, Fig. 2] first specimen from Sacrau near Gogolin, kept in a private collection [Grundey]), the other a complete skull exposed in ventral view (Schrammen's [1899, PI. 23, Fig. 3] second specimen from Krappitz [Krapkowice], kept in his own collection). The first specimen cannot be located today; the second specimen (smns 10109) has been prepared from the dorsal side for this study. As emphasized by Schrammen (1899), Cymatosaurus gracilis differs from Cy- matosaurus silesiacus mainly in absolute size. Schrammen's (1899) "second" specimen of Cy- matosaurus gracilis measures 98 mm from the tip of the snout to the back end of the parietal skull table; his "first" specimen of Cymatosaurus si- lesiacus measures approximately 145 mm (an un- described and rather poorly preserved specimen [bgr S 44/3] has a corresponding skull length of 125 mm). Apart from absolute size, Cymatosau- rus gracilis differs from Cymatosaurus silesiacus by relatively larger orbits. In Cymatosaurus grac- ilis the distance from the external naris to the orbit equals less than 2.5 times the width of the post- orbital arch, whereas in Cymatosaurus silesiacus it exceeds 2.5 times the width of the postorbital arch. In Cymatosaurus gracilis, the width of the dorsal bridge between the orbits is less than twice the width of the dorsal bridge between the nares; in Cymatosaurus silesiacus, it exceeds twice the width of the bridge between the external nares. Because the orbit grows with negative allometry in sauropterygians, relatively large orbits in rela- tively small skulls are not diagnostic of a separate species, and Cymatosaurus gracilis is considered to be represented by juvenile individuals. Schrammen (1899) described Cymatosaurus si- lesiacus on the basis of two skulls. His first spec- imen, from Sacrau near Gogolin (Schrammen, 1899, Pis. 21-22), was kept in a private collection (Grundey) and cannot be located in public repos- itories today. The second specimen, a fragmentary skull associated with postcranial remains from Krappitz [Krapkowice], was kept in Schrammen's own collection and likewise cannot be located in public repositories today. The skull of the "first" specimen described by Schrammen (1899) was fairly well preserved, and although the dermal bones were all finely broken, Schrammen (1899) asserted that sutures could be identified with great confidence. As described by Schrammen (1899), Cymatosaurus silesiacus shows an interesting combination of features such as nasals entering the posterior margin of the external naris, pre- frontal and postfrontal in contact along the dorsal margin of the orbit, and exclusion of the frontal from the anteromedial margin of the upper tem- poral fossa. Cymatosaurus silesiacus shares with Cymatosaurus gracilis (but not with Cymatosau- rus fridericianus) a single maxillary tooth preced- ing the paired maxillary fangs. Comparison to the outgroup (Nothosauridae: Rieppel, 1994b) shows RIEPPEL: REVISION OF CYMATOSAURUS Fig. 5. The skull of the neotype of Cymatosaurus latifrons (Giirich, 1884) (smns 10109), from the lower Muschel- kalk of Krapkowice, Upper Silesia. A, Dorsal view; B, ventral view. Scale bar = 20 mm. this to be a derived character, diagnostic of a sep- arate species for which Cymatosaurus latifrons Giirich, 1884, takes priority. Morphological Description — The description of the skull will primarily be based on the neotype (smns 10109; Figs. 5-6); reference will be made to the referred specimen smns 10977 (Rieppel, 1994b, Fig. 11) where necessary. In contrast to smns 10977, the neotype is strongly compressed dorsoventrally, and its small size indicates a ju- venile status. Reference of both skulls to Cyma- tosaurus is corroborated by the paired frontals and the incompletely fused parietals, the contact of prefrontal and postfrontal along the dorsal margin of the orbit, the restriction of the maxillary tooth row to a level in front of the anterior margin of the upper temporal fossa, and the location of the pineal foramen at the center of the parietal skull table. Total length of the skull of smns 10109 (as pre- served) is 104 mm; the distance from the tip of the snout to the posterior end of the parietal skull table measures 98 mm. The rostrum is narrow and elongated. Its relative length does not differ in C latifrons and in C fridericianus: dividing the dis- tance from the tip of the snout to the anterior mar- gin of the orbit by the distance from the tip of the snout to the anterior margin of the external naris 10 FIELDIANA: GEOLOGY Fig. 6. The skull of the neotype of Cymatosaurus latifrons (Gurich, 1884) (smns 10109) from the lower Muschel- kalk of Krapkowice, Upper Silesia. A, Dorsal view; B, ventral view. Scale bar = 20 mm. Abbreviations: ec, ecto- pterygoid; f, frontal; m, maxilla; n, nasal; p, parietal; pi, palatine; pm, premaxilla; po, postorbital; pof, postfrontal; prf, prefrontal; pt, pterygoid; q, quadrate; v, vomer. yields values of 1.87 for the holotype of C. fri- dericianus and 2.0 for the neotype of C latifrons. Dividing the distance from the tip of the snout to the anterior margin of the upper temporal fossa by the distance from the tip of the snout to the anterior margin of the external naris yields values of 2.68 for the holotype of C. fridericianus and 3.0 and for the neotype of C. latifrons. The some- what larger value in the latter species may be due to relatively larger orbits in this juvenile speci- men. Dividing the distance from the tip of the snout to the anterior margin of the external naris by the maximum width of the premaxillary ros- trum yields values of 1.4 for the holotype of C. fridericianus and 1.2 for the neotype of C. lati- frons. Dividing the dorsal bridge between the or- bits by the dorsal bridge between the external nar- es yields values of 2.4 for the holotype of C fri- dericianus and 1 .6 for the neotype of C. latifrons. This indicates a relatively narrower dorsal bridge between the orbits in the latter species, again a consequence of relatively large orbits in this ju- venile specimen. Schrammen's (1899) first speci- men of C "gracilis" would show a correspond- ing ratio of 1.5, whereas in the larger C. "silesi- acus" (Schrammen, 1899; first specimen) the ra- tio is 2.9. The original holotype of Cymatosaurus latifrons Gurich, 1884, again a relatively small skull (tip of snout to posterior end of parietal skull table approximately 100 mm), shows a corre- sponding value of 1.7. The relatively large size of the orbits is also borne out by the quotient which results from division of the distance between the external naris and the orbit by the distance be- tween the orbit and the upper temporal arch. The quotient is 2.8 for the holotype of C fridericianus and 2.3 for the neotype of C latifrons. Schram- men's (1899) first specimen of C. "gracilis" would show a corresponding ratio of 1 .7, whereas in the larger C. " silesiacus" (Schrammen, 1899; first specimen) the ratio is 2.6. The paired premaxillae meet the maxillae at the anterolateral corner of the external naris, and they form a broad and interdigitating contact with the RIEPPEL: REVISION OF CYMATOSAURUS 11 Fig. 7. The holotype of Cymatosaurus erythreus E.v. Huene, 1894 (bgr 612), from the upper Buntsandstein of Riidersdorf near Berlin, A, Dorsal view; B, ventral view. Scale bar = 20 mm. paired frontals between the nasals, at a level be- tween the external nares and the orbits. The ex- ternal nares are relatively broad and rounded. The left nasal cannot be identified in smns 10109 be- cause of excessive original preparation of the in- ternal naris, but the reduced right nasal can be seen to be excluded from the posterior margin of the external naris, unlike in Schrammen's (1899, PI. 23, Fig. 2) "first specimen" of C. "gracilis"; in that respect, the latter specimen resembles the holotype of C. silesiacus (Schrammen, 1899, PI. 21). Laterally, the nasal remains separated from the prefrontal by a broad contact between an an- terolateral process of the frontal and the maxilla. Exclusion of the reduced nasals from the external naris and separation of the nasal from the pre- frontal by a frontal-maxillary contact are also ob- served in smns 10977. The prefrontal appears as a rather slender element in dorsal view, lining the anterodorsal margin of the orbit and establishing a contact with the postfrontal that excludes the frontal from the orbit (unlike in Schrammen's [1899, PI. 23, Fig. 2] first specimen, but as in the holotype of C. silesiacus, and as in smns 10977). The frontal forms a distinct posterolateral process that remains narrowly excluded from the antero- medial margin of the upper temporal fossa (as in Schrammen's "first specimen," the posterolateral process of the frontal approaches the upper tem- poral fossa less closely in smns 10977). The post- frontal is a relatively broad element that defines the posterodorsal margin of the orbit as well as the anteromedial margin of the upper temporal fossa. It meets the postorbital in a deeply inter- digitating suture within the postorbital arch. The lateral (ventral) part of the postfrontal, and its re- lation to the jugal and to the upper temporal arch, are not preserved on either side of the skull, smns 10977 shows the postorbital to meet the squa- mosal in a broadly overlapping suture within the upper temporal arch. The jugal is a curved ele- ment without posterior process that defines the posteroventral corner of the orbit. The interdigitating frontoparietal suture is lo- cated between the anterior parts of the upper tem- poral fenestrae. To judge from the shape of the lateral margin of the parietal, the anterior, medial, and posterior margins of the relatively broad up- per temporal fossa were more or less evenly curved. The pineal foramen is located at the cen- ter of the parietal skull table. In front of the pineal foramen, a distinct suture separates the paired pa- rietals (the parietals are fully fused in smns 10977). Behind the pineal foramen, the parietal is distinctly constricted but not developed into a sag- ittal crest. No trace of a medial longitudinal suture 12 FIELDIANA: GEOLOGY Fig. 8. The holotype of Cymatosaurus erythreus E.v. Huene, 1894 (bgr 612), from the upper Buntsandstein of Riidersdorf near Berlin. A, Dorsal view; B, ventral view. Scale bar = 20 mm. Abbreviations; f, frontal; m, maxilla; pi, palatine; pm, premaxilla; prf, prefrontal; v, vomer. can be identified in the constricted posterior part of the parietal skull table. Preservation of the occiput is incomplete in smns 10109. As preserved, the skull contours in- dicate a deeply concave occiput and a limited oc- cipital exposure of the parietal. Poor preservation makes it impossible to trace the suture between the parietal and squamosal. All posterior braincase elements (supraoccipital, exoccipitals, opisthotic, and basioccipital [occipital condyle]) are missing. This indicates a loose connection between the braincase and the dermatocranium, which might be attributed to the juvenile status of the speci- men. However, all posterior braincase elements are also missing in the larger specimen smns 10977, as indeed in every other specimen of Cy- matosaurus available today. It is for this reason that a tight association of the braincase with the dermatocranium in the formation of a closed, plate-like occiput (as seen in Simosaurus and No- thosaurus) is believed to be absent in Cymatosau- rus (characters 3 1 and 32 of the cladistic analysis, discussed below). The suspensorium appears to be distinctly flaring in smns 10109, carrying the mandibular articulation to a position well lateral of the posterior corner of the upper temporal fos- sa. This is, however, an artifact of dorsoventral crushing of the skull. In the three-dimensionally preserved specimen smns 10977, the suspenso- rium is more vertically oriented, and the mandib- ular articulation is positioned below the posterior end of the upper temporal fossa, as is typical for the genus in general. The ventral view of the skull shows five pre- maxillary tooth positions and a single maxillary tooth preceding the paired maxillary fangs (three maxillary teeth precede the paired maxillary fangs in C. fridericianus). Behind the maxillary fangs, 10-11 tooth positions can be counted, bringing the total number of maxillary teeth up to 13-14. The same tooth count is obtained in smns 10977. Posteriorly, the maxillary tooth row does not ex- tend beyond the level of the posterior margin of the orbit. The internal nares are relatively shorter than in C. fridericianus (division of the longitu- dinal diameter by the transverse diameter yields a ratio of 1.6 for smns 10109), but as in the latter species, and unlike Nothosaurus, the internal naris is positioned somewhat further back relative to the external naris (Table 1). A narrow fontanelle ("foramen incisivum") separates the premaxillae in ventral view. The paired vomers meet the maxillae at the anterior margin of the internal nares, thus excluding the RIEPPEL: REVISION OF CYMATOSAURUS 13 premaxillae from the latter. Posteriorly, the vo- mers meet the pterygoids in an interdigitating su- ture. The posterior margin of the internal naris is defined by the palatine. The exact contours of the ectopterygoid cannot be identified, but the pres- ence of a well-developed (ecto-)pterygoid flange is distinct on the left side of the skull. Posteriorly, the pterygoid shows well-developed lateral and medial ventral flanges for the origin of the pter- ygoideus musculature. Cymatosaurus multidentatus (F.v. Huene, 1958) 1958 Anarosaurus multidentatus, F.v. Huene, pp. 382-384. 1995c Cymatosaurus multidentatus, Rieppel, p. 288. Holotype — Incomplete lower jaw (Mbg 4791). Locus Typicus — Lowermost lower Anisian (6 m above the base), Krabachmasse, Trittwangkopf, NNW Stuttgarter Hiitte, Lechtaler Alpen (Arl- berg), Austria. Diagnosis — A very incompletely known spe- cies of Cymatosaurus of small size, characterized by a distinctly heterodont dentition. Referred Specimens — Mbg 4792 (isolated tooth [Huene, 1958, Fig. 2], fragmentary verte- bra); Mbg 4793 (isolated tooth [Huene, 1958, Fig. 3]. ?metatarsal [Huene, 1958, Fig. 6]); Mbg 4794 (vertebral centrum [Huene, 1958, Fig. 24); Mbg 4795 (fragmentary vertebral centrum [Huene, 1958, Fig. 5]). Comments — This species was redescribed by Rieppel (1995c). Cymatosaurus sp. ("C. erythreus" E.v. Huene, 1944) Synonymy for this material: 1994 Cymatosaurus erythreus, E.v. Huene, pp. \93ff., Figs. la-c. 1964 Cymatosaurus erythreus, Kuhn, p. 13. 1995c Cymatosaurus erythreus, Rieppel, p. 295, Figs. 7, 8C. Holotype — Snout fragment (brg 612; Figs. 7, 8). Locus Typicus — Upper Buntsandstein (so2, Rot), Rudersdorf near Berlin. Referred Specimen — An isolated parietal (Fig. 9; bgr 613; original of E.v. Huene, 1994, p. 200, Fig. 2 in her paper) from the same locality and horizon as the holotype. Comments — This species was described by E.v. Huene (1944) on the basis of an incomplete skull that represents the earliest occurrence of the genus Cymatosaurus in the Germanic Triassic. The frag- ment (Figs. 7, 8) comprises most of the preorbital skull and has a total length of 58.4 mm (as pre- served). The distance from the tip of the snout to the anterior margin of the external naris is 29 (28) mm, to the anterior margin of the orbit 54 mm. The longitudinal diameter of the external naris is 12.2 mm, and the bridge between the external nar- is and the orbit is 13.5 mm wide. The width of the snout at the level of the anterior margins of the external nares is 23.5 mm; the total width of the premaxillary rostrum (at the fourth tooth po- sition) is 25.7 mm. The longitudinal diameter of the internal naris is 9.5 mm. The rostrum is of similar relative length as in the genotypical species, Cymatosaurus friderici- anus Fritsch (1894), or, indeed, as in other species of Cymatosaurus. Dividing the distance from the tip of the snout to the anterior margin of the orbit by the distance from the tip of the snout to the anterior margin of the external naris results in a ratio of 1.89 for Cymatosaurus erythreus, com- pared to 1.87 for Cymatosaurus fridericianus. The rostrum is formed by the premaxillae. Broad posterior (nasal) processes of the premax- illae separate the external nares from one another and meet the frontals in a deeply interdigitating suture at a level between the external nares and the orbits. The preserved anterior ends of the fron- tals show these elements to be paired, as is char- acteristic of the genus Cymatosaurus. Damage to the bone surface has rendered the accurate delineation of the nasals impossible. However, the nasal extends anteriorly along the medial margin of the external naris in those stem- group sauropterygians that do not show reduction of these elements. No participation of the nasals can be identified in the medial margins of the ex- ternal nares in Cymatosaurus erythreus, indicating reduction of these bones. Likewise, the left exter- nal naris indicates the exclusion of the nasal from its posterior margin, another feature diagnostic for (some) Cymatosaurus. The prefrontal is exposed at the anterodorsal margin of the left orbit. A lacrimal is lacking 14 FIELDIANA: GEOLOGY Fig. 9. An isolated parietal referred to Cymatosaurus erythreus E.v. Huene, 1894 (bgr 613), from the upper Buntsandstein of Rudersdorf near Berlin. Scale bar - 20 (contra E.v. Huene, 1944, p. 195), and the lacri- mal duct is enclosed entirely within the maxilla, as is also observed in Nothosaurus. The ventral aspect reveals relatively short and broad internal nares, a feature shared with other species of Cymatosaurus but a contrast to the rel- atively narrow and elongated internal nares ob- served in Nothosaurus (except N. marchicus). The posterior margin of the internal naris is defined by the palatine and its medial margin by the (paired) vomer. Vomer and maxilla meet in a broad contact at the anterior margin of the internal naris, thus excluding the premaxilla from the latter. Between the premaxillae and in front of the vomers, a fon- tanelle persists, a feature shared with Cymatosau- rus, Pistosaurus (Fritsch, 1 894), and Nothosaurus (Rieppel & Wild, 1996). The right premaxilla car- ries five tooth positions; the size of the alveoli indicates that the third and fourth teeth were the largest. Three small maxillary teeth precede the paired maxillary fangs. The replacement pits, lo- cated posteromedial to the functional tooth posi- tions, are more distinctly elongated and drop- shaped than in Nothosaurus, and most of them are confluent with the alveoli of the functional teeth. The skull fragment described by E.v. Huene (1944) as Cymatosaurus erythreus is unquestion- ably a representative of that genus, as is indicated by a number of characters, most notably the ex- clusion of the (reduced) nasals from the external naris and the paired condition of the frontals. The specimen is too incomplete, however, to be diag- nostic for a separate species. Within the genus, it shares with Cymatosaurus fridericianus three small maxillary teeth preceding the maxillary fangs, but this is a plesiomorphic trait in compar- ison to the outgroup (Nothosauridae). Therefore, Cymatosaurus erythreus E.v. Huene, 1944, is here considered a nomen dubium. Nothosauridae Baur, 1889 Definition — A monophyletic taxon including the genera Germanosaurus Nopcsa, 1928a, No- thosaurus Miinster, 1834, and Lariosaurus Cu- rioni, 1847 (Ceresiosaurus Peyer, 1931, and Sit- vestrosaurus Kuhn-Schnyder, 1990, are here con- sidered junior synonyms of Lariosaurus: Rieppel, 1993, and in prep.). Diagnosis — Small to large eosauropterygians with a strongly depressed skull; snout constricted; dorsal exposure of prefrontal reduced; jugal (usu- ally) excluded from posterior margin of orbit; pre- maxillary and anterior dentary fangs present. Distribution — Lower to Upper Triassic, Eu- rope and Israel. Comments — Within the Nothosauridae, Ger- manosaurus is the sister-taxon of a monophyletic clade (Nothosaurinae: Nopcsa, 1923, 1928a,b) in- cluding the genera Nothosaurus and Lariosaurus. Diagnostic characters of the Nothosaurinae are frontals fused, parietal skull table strongly con- stricted, maxillary fangs present, occipital crest present, supraoccipital horizontally oriented and fused with parietal, occipital crest present, man- dibular symphysis strongly elongated and fortified (not known for Germanosaurus), unconstricted vertebral centra (not known for Germanosaurus), and no distal expansion of sacral ribs (not known for Germanosaurus). Germanosaurus Nopcsa, 1928 1903 Eurysaurus, Freeh, p. 15. 1924 Eurysaurus, Arthaber, p. 476. RIEPPEL: REVISION OF CYMATOSAURUS 15 1928a Germanosaurus, Nopcsa, pp. 21, 44. 1928b Germanosaurus, Nopcsa, p. 173. 1944 Cymatosaurus {Germanosaurus) (par- tim), E.v. Huene, p. 208. Type Species — Germanosaurus latissimus Giir- ich, 1891, from the lower Muschelkalk, lower Middle Triassic, Sacrau, Upper Silesia. Definition — A monophyletic taxon including the species schafferi. Diagnosis — A large eosauropterygian with a constricted snout and a relatively short and broad rostrum. Posterolateral process of paired frontals closely approaches upper temporal fossa; parietals paired. Comments — Of the two species described in the genus, Germanosaurus latissimus (Giirich, 1891) and Germanosaurus schafferi (Arthaber, 1924), only the latter is represented by original material available today. Germanosaurus sp. ("G. latissimus" [Giirich, 1891]) Synonymy for this material: 1891 Nothosaurus latissimus, Giirich, p. 968, Figs. a-b. 1893 Nothosaurus latissimus, Koken, p. 368 ff, Figs. 6-11. 1899 Cymatosaurus (Nothosaurus) latissi- mus, Schrammen, p. 388/ 1903 Nothosaurus (Eurysaurus) latissimus, Freeh, p. 15, Fig. 1. 1914 Nothosaurus (Eurysaurus) latissimus, Schroder, p. 78. 1914 Eurysaurus latissimus, Schroder, p. 82 ff, Fig. 22. 1924 Eurysaurus latissimus, Arthaber, p. 476/ 1928 Eurysaurus latissimus, Schmidt, p. 395, Fig. 1110. 1934 Germanosaurus latissimus, Kuhn, p. 41. 1944 Cymatosaurus latissimus, E.v. Huene, p. 199. 1944 Cymatosaurus (germanosaurus) latissi- mus, E.v. Huene, p. 208. 1964 Cymatosaurus latissimus, Kuhn, p. 13. Holotype — The skull described by Giirich (1891) and figured by Koken (1893, Fig. 10) and Freeh (1903, Fig. 1) can no longer be located in public repositories. Locus Typicus — Lower Muschelkalk (Gogolin beds, mu,), Sacrau near Gogolin, Upper Silesia (Poland). Comments — The taxonomic status of "Cyma- tosaurus" latissimus (Giirich, 1891) can no longer be critically evaluated because the original (type) material has been lost. The situation is aggravated by the fact that Giirich (1891, figure on p. 968) included only a very schematic figure in his orig- inal description of the species. The skull was pre- served in two parts and estimated by Giirich (1891) to be approximately 270 mm long. With this size, the specimen is distinctly larger than any specimen of Cymatosaurus but closely approach- es the holotype of Germanosaurus schafferi (Ar- thaber, 1924). Koken (1893, Fig. 11) indicates four maxillary teeth preceding the paired maxil- lary fangs, a character that separates "Cymato- saurus'''' latissimus from the known species of Cy- matosaurus. In other respects, however, "Cyma- tosaurus" latissimus resembles Germanosaurus schafferi, with which it shares the reduced nasal bones that enter the posterior margin of the ex- ternal nares, the paired frontals, the restricted dor- sal exposure of the prefrontals (broadly exposed in Cymatosaurus), which do not contact the post- frontal along the dorsal margin of the orbit, and a jugal bone that extends alongside the postorbital into the upper temporal arch (the jugal does not extend into the upper temporal arch in Cymato- saurus as shown by the specimen smns 10977). Whether the jugal does, indeed, broadly enter the ventral margin of the orbit in "Cymatosaurus" latissimus (Koken, 1893, Fig. 10), or whether is was excluded therefrom, can no longer be as- sessed. In view of its large size and the characters outlined above, "Cymatosaurus" latissimus is here referred to the genus Germanosaurus. Ger- manosaurus latissimus (Giirich, 1891) is here treated as a nomen dubium rather than as a senior synonym of Germanosaurus schafferi (Arthaber, 1924), because loss of the holotype (and only known specimen) prevents critical comparison with the latter species. Fig. 10. The skull of the holotype of Germanosaurus schafferi (Arthaber, 1924) (nhmw, uncatalogued), from the lower Muschelkalk of Gogolin, Upper Silesia, in dorsal view. Scale bar = 50 mm. (Courtesy of Dr. G. Hock, Natural History Museum, Vienna.) 16 FIELDIANA: GEOLOGY RIEPPEL: REVISION OF CYMATOSAURUS 17 Fig. 11. The skull of the holotype of Germanosau- rus schqfferi (Arthaber, 1924) (nhmw, uncatalogued), from the lower Muschelkalk of Gogolin, Upper Silesia, in dorsal view. Scale bar = 50 mm. Abbreviations: f, frontal; ju, jugal; m, maxilla; n, nasal; p, parietal; pm, premaxilla; po, postorbital; pof, postfrontal; prf, prefron- tal; sq, squamosal. Germanosaurus schafferi (Arthaber, 1924) 1924 Eurysaurus schafferi, Arthaber, p. 1476 ff, Figs, lla-b. 1928 Eurysaurus schafferi, Schmidt, p. 395, Fig. 1111. 1934 Germanosaurus schafferi, Kuhn, p. 42. 1944 Cymatosaurus {Germanosaurus) schaf- feri, E.v. Huene, p. 208/ 1964 Cymatosaurus schafferi, Kuhn, p. 12. Holotype — Skull (nhmw, uncatalogued; Figs. 10, 11). Locus Typicus — Lower Muschelkalk (Gogolin beds, rau,), Gogolin, Upper Silesia (Poland). Fig. 12. An isolated parietal referred to Germano- saurus schafferi (Arthaber, 1924) (bgr, uncatalogued), from the lower Muschelkalk of Gogolin, Upper Silesia. Scale bar = 50 mm. Abbreviations: f, frontal; p, parietal. Diagnosis — Same as for genus, of which this is the only species represented by original mate- rial today. Distribution — Lower Muschelkalk (lower An- isian, lower Middle Triassic), central Europe. Referred Specimens — Isolated parietal (Fig. 12) from the lower Muschelkalk (Gogolin beds, mu,), Gogolin, Upper Silesia (bgr, uncatalogued; Rieppel, 1994a, Fig. 40). Morphological Description — Germanosaurus schafferi is known from a single skull prepared in dorsal view (Fig. 11). The distance from the tip of the snout to the back end of the parietal skull table measures 244 mm, which is distinctly longer than in the skulls referred to the genus Cymato- saurus but approaches the size of "Cymatosau- rus" latissimus (see above). The rostrum is rela- tively broader than in skulls referred to the genus Cymatosaurus, with the consequence that the ros- tral constriction is more pronounced in Germa- nosaurus. Dividing the distance from the tip of the snout to the anterior margin of the external Table 2. Data matrix for the cladistic analysis of all Cymatosaurus species ever described. Character defini- tions are given in the Appendix. 1 1 2 3 4 5 1 erythreus 1 ? ? ? ? 2 fridericianus 1 1 1 0 0 3 gracilis I 0 0 0 ? 1 4 gracilis II 1 1 0 1 1 5 latifrons 1 1 0 ? 0 6 latissimus 0 0 0 ? ? 7 silesiacus I 0 1 0 1 0 8 SMNS 10977 0 1 0 ? ? 9 BRG uncat ? 1 1 ? ? 1 0 AII-0-Anc 0 0 0 0 0 FIELDIANA: GEOLOGY Captorhinidae Testudines Araeoscelidia Younginiformes Claudiosaurus Placodus Corosaurus Cymatosaurus Pistosaurus Dactylosaurus Serpiano-Neustico Simosaurus Germanosaurus Nothosaurus Lariosaurus Fig. 13. Strict consensus tree (2 MPTs, TL = 283, CI = 0.675, RI = 0.702) for a monophyletic Sauropter- ygia rooted on Captorhinidae, Araeoscelidia, Youngini- formes, Claudiosaurus, and Testudines. For further dis- cussion see text. naris by the maximum width of the premaxillary rostrum yields values of 0.94 (left side) and 1 .03 (right side) for the holotype of Germanosaurus schafferi, 1 .4 for the holotype of C. fridericianus, and 1.2 for the neotype of C. latifrons. Dividing the distance from the tip of the snout to the an- terior margin of the orbit by the distance from the tip of the snout to the anterior margin of the ex- ternal naris yields a value of approximately 1.8 for the holotype of Germanosaurus schafferi, 1 .9 for the holotype of C. fridericianus, and 2.0 for the neotype of C. latifrons. Dividing the distance from the tip of the snout to the anterior margin of the upper temporal fossa by the distance from the tip of the snout to the anterior margin of the ex- ternal naris yields a value of approximately 2.86 for the holotype of Germanosaurus schafferi, 2.7 for the holotype of C. fridericianus, and 3.0 for the neotype of C latifrons. Dividing the longitu- dinal diameter of the upper temporal fossa by the longitudinal diameter of the orbit yields a value of 1 .9 for the holotype of Germanosaurus schaf- Ancestor Captorhinidae Araeoscelidia Claudiosaurus Younginiformes Archosauriformes Rhynchosauria Trilophosaurus Prolacertiformes Choristodera Kuehneosauridae Rhynchocephalia Squamata Testudines Placodus Corosaurus Cymatosaurus Pistosaurus Dactylosaurus Serpiano-Neustico Simosaurus Germanosaurus Nothosaurus Lariosaurus Fig. 14. Strict consensus tree (2 MPTs, TL = 452, CI = 0.648, RI = 0.71 1) for 23 ingroup taxa rooted on an all-0 ancestor. For further discussion see text. feri, which falls into the upper range of variability of Cymatosaurus (1.3-2.0) and in between the range of variability between relatively plesiom- orphic {Nothosaurus marchicus) and apomorphic {Nothosaurus mirabilis) representatives of the ge- nus Nothosaurus. Indeed, the skull of Germano- saurus schafferi shows an intriguing combination of characters otherwise typical of Cymatosaurus or Nothosaurus. The adult stage of Germanosaurus is indicated by the fusion of the premaxillae in the anterior part of the rostrum. The premaxilla meets the maxilla at the anterolateral edge of the external naris, in a suture that trends anterolaterally. In Cy- matosaurus and Nothosaurus, the maxilla shows a distinct lateral bulging in the area between the external nares and orbits, which accommodates the roots of the paired maxillary fangs. In Ger- manosaurus, the lateral contours of the skull show a lateral bulging at the level of the external nares, but whereas the four, perhaps five, premaxillary teeth (fangs) are distinctly larger than the maxil- lary teeth, no maxillary fangs are observed either at the level of the lateral bulging of the maxilla RIEPPEL: REVISION OF CYMATOSAURUS 19 Sauropterygia 2 £ •2 3 w Pachypleurosauroidea Nothosauridae Fig. 15. Clade rank determination in Sauropterygia. Pachypleurosaur interrelationships are based on an in- dependent study (Rieppel & Lin Kebang, 1995). For fur- ther discussion see text and Norell and Novacek (1992). or behind it at the level between the external naris and the orbit. Because a small maxillary tooth is preserved (in the left maxilla) in the position where other Eosauropterygia carry paired maxil- lary fangs (between the external naris and the or- bit), it is concluded that such fangs are absent in Germanosaurus (alternatively, one might assume that both fangs have been shed, and a replacement tooth is observed in situ, in which case the max- illary fangs would be a synapomorphy of the No- thosauridae rather than of the Nothosaurinae). Germanosaurus differs from Nothosaurus, but resembles some specimens of Cymatosaurus, in that the nasals are reduced but still reach the pos- terior margin of the external nares. As in Cyma- tosaurus, but unlike Nothosaurus, there is no slen- der anterior process of the nasal lining the medial margin of the external naris that is defined by the premaxilla. Posteriorly, the nasals taper to a blunt tip that is embraced between an anterolateral and an anteromedial process of the frontal. At the lev- el of the anterior margin of the orbit, the antero- medial process of the frontal meets the posterior (nasal) process of the premaxilla, which separates the nasals from one another. The anterolateral pro- Sauropterygia 7 ♦ 6 * c 1 5 * d 4 * e r 3 *? * a n 2 k * 1 * so2 mul | mu2 1 mu3 | mm | mol mo2| mo3 A SCYTHIAN ANISIAN LADINIAN age rank Pachypleurosauroidea B 5 * 4 * 3 * 2 * 1 9 so2 mul mu2 mu3 mm mol mo2 mo3 age rank Nothosauridae 3 • • * clade rank 2 Ceresiosaurus j, Silvestrosaurus 1 * c so2 mul mu2|mu3 mm mol mo2 mo3 age rank Fig. 16. Graphic representations of clade versus age rank for Triassic Sauropterygia (A), Pachypleurosauroi- dea, (B), and Nothosauridae (C). For further discussion see text. cess of the frontal separates the nasal from the prefrontal. As in Nothosaurus, but unlike Cymatosaurus, the dorsal exposure of the prefrontal is distinctly reduced. Yet, as in Cymatosaurus but unlike No- thosaurus, the frontals are paired. Since the pre- frontal does not contact the postfrontal, the frontal . D FIELDIANA: GEOLOGY Table 3. Data matrix for the cladistic analysis of sauropterygian interrelationships. Character definitions are given in the Appendix. See Rieppel (1994a) and text for further discussion. 1 1 2 3 4 « 6 7 8 9 1 0 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 0 0 0 0 0 3 Testudines 0 0 0 0 0 0 0 0 1 0&1 4 Araeosceiidia 0 0 0 0 0 0 0 0 0 0 5 Younginiformes 0 0 0 0 0 0 0 0 1 0 6 Kuehneosauridae 0 0 0 0 0 0 0 0 1 0 7 Rhynchocephalia 0 0 0 0 0 0 0 0 1&2 0 8 Squamata 0 0 0 0 0 0 0 0 1&2 0&1 9 Rhynchosauria 1 0 0 0 0 0 0 1 0 1 0 Prolacertiformes 1 0 0 1 0 0 0 1 0 1 1 Trilophosaurus 1 ? 0 0 0 0 0 0 ? 1 1 2 Choristodera 1 0 0 1 0 0 0 1 0 1 3 Archosauriformes 1 0 0 1 0 0 0 1 0 1 4 Claudiosaurus 0 0 0 0 0 0 0 0 1 0 1 5 Dactylosaurus 1 0 0 0 0 0 0 0 2 0 1 6 Serpiano-Neustico 1 0 0 0 0 0 0 0&1 2 0 1 7 Simosaurus 1 0 0 0 0 1 0 1 2 0 1 8 Nothosaurus 1 0 1 1 0 0 0 0&1 2 0 1 9 Lariosaurus 1 0 1 1 0 0 0 0&1 2 0 20 Corosaurus 1 0 0 0 0 0 0 0 2 0 2 1 Cymatosaurus 1 0 1 0 0 2 0&1 1 2 0&1 22 Germanosaurus 1 0 1 1 0 1 0 1 2 0 2 3 Pistosaurus 1 0 0 0 0 2 1 1 2 0 24 Placodus 1 0 1 0 1 0 0 0 2 1 broadly enters the dorsal (medial) margin of the orbit. Posteriorly, the frontals form well-defined posterolateral processes that embrace an antero- medial extension of the parietals. The exact lo- cation of the posterior tips of the frontals is dif- ficult to ascertain due to damaged bone surface. Arthaber (1924, Fig. 1 lb) shows the posterolateral process of the frontal broadly entering the antero- medial margin of the upper temporal fossa. Closer inspection of the specimen indicates, however, that the parietal meets the postfrontal in a narrow suture along the anteromedial margin of the upper temporal fossa, thus excluding the frontal from the latter. The postorbital arch is composed of the post- frontal and postorbital. The postfrontal defines the posterodorsal (-medial) margin of the orbit as well as the anteromedial margin of the upper temporal fossa. It shows a distinct postorbital constriction, as is also observed in some specimens of Notho- saurus (N. marchicus). The postorbital defines the posteroventral (-lateral) margin of the orbit and meets the squamosal in a broadly overlapping su- ture within the upper temporal arch. The anterior part of the postorbital is clearly delineated by a suture entering the posteroventral (-lateral) margin of the orbit. At the level of the anterior margin of the post- orbital, a distinct and deeply interdigitating suture trends laterally, marking the anterior end of the relatively broad jugal. This indicates that the ven- tral (lateral) margin of the orbit is formed by the maxilla and that the jugal remains excluded from the orbit as in most specimens of Nothosaurus, but unlike Cymatosaurus. The jugal extends pos- teriorly into the upper temporal arch lateral to the postorbital, but its exact delineation from the an- terior process of the squamosal cannot be identi- fied. An overlapping contact between the jugal and squamosal must be inferred from the general topology of the bones. The posterior end of the maxilla is difficult to identify in this incompletely RIEPPEL: REVISION OF CYMATOSAURUS 21 Table 3. Continued. 2 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 20 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 ? 0 0&2 0 0 3 Testudines 0 0&2 0 0 0 ? 0 3 0 1 4 Araeoscelidia 0 1 0 1 0 0 0 0 0 5 Younginiformes 0 1 0 1 0 0 0 0 0 6 Kuehneosauridae 0 0 0 1 0 0 2 0 7 Rhynchocephalia 0 0 0&1 0&1 0 0&1 0&2 0&2 8 Squamata 0 0&1&2 A 0&1 0 0 0&1 0&2&3 0&2 9 Rhynchosauria 0 0 0 0 0 1 3 3 1 0 Prolacertiformes 0 1 0 0&1 0 0&1 2&3 0 1 1 Trilophosaurus 0 1 0 0 1 0 3 3 1 2 Choristodera 0 2 0 0 0 0 3 1 1 3 Archosauriformes 0 0&1 0&1 0&1 0&1&2 0&1 0&3 0&2 1 4 Claudiosaurus 0 1 0 0 0 0 0 1 5 Dactylosaurus 0 1 3 0 0 0 0 0 1 6 Serpiano-Neustico 0 1 3 0 0 0 0 0 1 7 Simosaurus 0 2 2 1 0 0 2 1 1 1 8 Nothosaurus 1 2 2 1 0 2 1 2&3 1 9 Lariosaurus 1 2 2 1 0 2 1 2 20 Corosaurus 0 0 1 0 1 0 0 1 2 1 Cymatosaurus 0 2 2 0 1&2 1 &2 0 2&3 22 Germanosaurus 1 2 2 0 1 1 1 1 23 Pistosaurus 0 1 2 0 2 1 2 3 24 Placodus 0 0 2 0&1 0 0&2 2 0 prepared skull, but it appears to lie at the level of the anterior margin of the upper temporal fossa, where a suture between the jugal and maxilla is apparent. The paired parietals form a skull table that is narrow but not as strongly constricted as is oth- erwise characteristic of Cymatosaurus or Notho- saurus. The pineal foramen is displaced posteri- orly to a point distinctly behind the center of the skull table but still remaining at some distance from the posterior margin of the parietal skull ta- ble, as is the case in some early representatives of Nothosaurus (undescribed material from Win- terswijk in private collections, and N. marchicus: Rieppel & Wild, 1996). The occiput is only partially preserved and/or prepared. No sutures are apparent that would in- dicate the exact relationships of parietal and squa- mosal. A deep posterior excavation of the occiput is apparent from the outline of the skull, indicat- ing posterolaterally trending paroccipital process- es. No supraoccipital is exposed in dorsal view, as would be the case in Nothosaurus, which may indicate that the supraoccipital was more vertical- ly oriented and/or only loosely connected to the dermatocranium as in Cymatosaurus. The palatal view is not prepared in Germano- saurus, but through the left external naris the an- terior margin of the internal naris is exposed, in- dicating the position of the internal naris, which lies relatively further back than is typical for No- thosaurus, but which corresponds to the position of the internal nares in Cymatosaurus (Table 1). Cladistic Analysis Earlier literature on the systematics of the ge- nus Cymatosaurus placed much emphasis on the reduction of the nasals and their relation to the posterior margin of the external naris. In the most recent review of the genus, E.v. Huene (1944) rec- ognized two subgenera, Cymatosaurus (Cymato- 22 FIELDIANA: GEOLOGY Table 3. Continued. 3 2 1 2 2 23 24 25 2 6 27 28 29 30 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 1 0 0 0 0 0 0 0 0 0 3 Testudines 1 0&1 0 0 0 ? 0 1 0 0 4 Araeoscelidia 0 0 0 0 0 1 0&1 0 0 0 5 Younginiformes 0&1 0 0 0 0 1 1 0 0 0 6 Kuehneosauridae 1 1 0 0 0 1 2 1 1 1 7 Rhynchocephalia 1 0&1 0&1 1 0 1 1&2 0 0 1 8 Squamata 1 0&1 0&1 0 0 1 2 1 1 ? 9 Rhynchosauria 1 1 0 1 0 1 1 1 0 0 1 0 Prolacertiformes 1 0&1 0 0&1 0 1 2 1 0&1 1 1 1 Trilophosaurus 1 ? 0 ? 0 1 0 ? 0 ? 1 2 Choristodera 1 1 0 0 0 1 1 1 0&1 0 1 3 Archosauriformes 1 0&1 0 1 0 1 1 1 0 0 1 4 Claud iosaurus 1 1 0 0 0 1 2 0 0 1 1 5 Dactylosaurus 1 1 7 0 0 2 2 0 0 1 1 6 Serpiano-Neustico 1 1 0 0 0 2 2 0 0 1 1 7 Simosaurus 1 1 0 0 1 1 2 0 0 1 1 8 Nothosaurus 1 1 1&2 0 1 1&2 2 0 0&1 1 1 9 Lariosaurus 1 1 1&2 0 1 2 2 0 ? ? 20 Corosaurus 1 1 ? 0 0 1 2 0 ? ? 2 1 Cymatosaurus 1 1 1 0 0 1 2 0 1 ? 2 2 Germanosaurus 1 1 2 0 1 1 2 0 ? ? 23 Pistosaurus 1 1 ? 0 1 1 2 0 1 ? 24 Placodus 1 1 0 0 1 1 2 0 0 0 saurus) and Cymatosaurus (Germanosaurus). The first would be characterized by the exclusion of the nasals from the external nares (erythreus, fri- dericianus, latifrons), the second by the entry of the nasals into the external nares (silesiacus, grac- ilis [in Schrammen's, 1899, first specimen, but not in his second specimen; see above], latissimus, schafferi). The description of the currently avail- able material shows a high degree of incongru- ence of this with other characters, such as the con- tact of the pre- and postfrontal at the dorsal mar- gin of the orbit, entry of the frontal into the an- teromedial margin of the upper temporal fossa, the number of maxillary teeth preceding the max- illary fangs, and the relative width of the dorsal bridge between the orbits. To test the monophyly of the two subgenera recognized by E.v. Huene (1944), a small data matrix (Table 2) was con- structed for the following characters: 1. Nasals entering (0) or excluded from (1) the posterior margin of the external naris. 2. Prefrontal and postfrontal do not (0) or do ( 1 ) meet along the dorsal margin of the orbit. 3. The frontal does not (0) or does (1) enter the anteromedial margin of the upper temporal fossa. 4. Three (0) or one ( 1 ) maxillary tooth preceding paired maxillary fangs. 5. Dorsal bony bridge between orbits larger (0) or smaller ( 1 ) than twice the width of the dor- sal bridge between the external nares. The data were analyzed using the software package PAUP version 3.1.1. developed by David L. Swofford (Swofford, 1990; Swofford & Begle, 1993). The branch-and-bound search for the shortest unrooted network (character 4 uninform- ative and hence ignored in the analysis) among all the previously described and currently available skulls of Cymatosaurus (9 terminal taxa, Table 2) yields a total of 57 most parsimonious trees (MPTs) with a tree length (TL) of 5 steps, a con- sistency index (CI) of 0.8, and a retention index RIEPPEL: REVISION OF CYMATOSAURUS 23 Table 3. Continued. 4 3 1 3 2 33 34 3 5 3 6 37 3 8 39 40 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 ? 0 0 0 0 0 0 3 Testudines 0 0 0&2 0 0 0 1 1 0 0 4 Araeoscelidia 0 0 0 1 0 0 0 0 ? 0 5 Younginiformes 0 0 0 1 0 0 ? 0 6 Kuehneosauridae 0 0 0 1 0 1 ? 1 7 Rhynchocephalia 0&1 0 0 1 0 0&1 1 0&1 8 Squamata 0 0 0&1&2 0&1 0&1 0&1 1 1 9 Rhynchosauria 1 0 0 0 0 0 1 0 1 0 Prolacertiformes 1 0 0 1 0 0 ? 0 1 1 Trilophosaurus 1 0 2 ? 0 ? 0 0 1 2 Choristodera 1 0 1 1 0 1 ? 0 1 3 Archosauriformes 0&1 0 0&1&2 1 0 0&1 ? 0 1 4 Claudiosaurus 0 0 0 ? 0 0 0 0 ? 0 1 5 Dactylosaurus 2 0 0 ? 1 0 1 0 1 6 Serpiano-Neustico 2 0 0 ? 1 0 1 0 1 7 Simosaurus 2 0 1 1 0 0 0 0 0 1 8 Nothosaurus 2 0 0&1 1 1 1 0 0 0 1 9 Lariosaurus 2 0 0 ? 1 1 0 0 0 20 Corosaurus 1 1 1 1 0 1 0 1 0 2 1 Cymatosaurus 1 1 1 ? 0 0&1 0 ? 0 22 Germanosaurus ? ? ? ? ? 0 0 ? 0 23 Pistosaurus 1 ? 1 ? 0 1 0 1 0 24 Placodus 1 0 0 1 0 0 1 1 0 (RI) of 0.833. The strict consensus tree shows no resolution except for a pairing of latissimus with Schrammen's (1899) first specimen of gracilis. The character that links these two taxa in the un- rooted network is the absence of a contact of pre- and postfrontal at the dorsal margin of the orbit, a plesiomorphy compared to outgroups (pachy- pleurosaurs, Simosaurus, Nothosauridae). If the branch-and-bound analysis is rooted on an all-0 ancestor (assuming monophyly of the genus Cy- matosaurus), all characters become informative. The branch-and-bound search yields a total of 383 MPTs (TL = 7, CI = 0.714, RI = 0.75), with a strict consensus tree that shows absolutely no res- olution among the terminal taxa. It is therefore concluded that there is no evidence for the mono- phyly of the subgenera recognized by E.v. Huene (1944). In fact, cladistic analysis at a more global scale indicates that a taxon comprising Cymato- saurus and Germanosaurus is nonmonophyletic. A global assessment of the phylogenetic rela- tionships of the genera Cymatosaurus and Ger- manosaurus within the Sauropterygia was based on the data matrix used in an earlier analysis of sauropterygian interrelationships (see Rieppel, 1994a, for an extensive discussion of characters and for references). The data matrix was substan- tially expanded, and some characters used earlier were redefined following the study of all original material of Cymatosaurus and Germanosaurus deposited in public repositories and after further preparation of the type material of Corosaurus from the Alcova Limestone of Wyoming (Storrs, 1991). Character definitions are given in the Ap- pendix; the coding of characters is given in Table 3. A full discussion of the characters will appear elsewhere, in conjunction with a redescription of Corosaurus. Discussion of characters will here be restricted to those relevant in the study of Cy- matosaurus and Germanosaurus. Simosaurus was recoded for character 6(1) in view of the fact that the nasals are as much re- duced in this genus as they are in Germanosaurus, a degree of reduction that is intermediate between 24 FIELDIANA: GEOLOGY Table 3. Continued. 5 4 1 4 2 43 4 4 45 4 6 47 4 8 4 9 50 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 1 0 0 0 0 3 Testudines 0&1 0 0 0&1 1 0 0&1 0 0 4 Araeoscelidia 0 0 0 0 0 0 0 0 0 5 Younginiformes 0 0 0 0 0 0 1 0 6 Kuehneosauridae 0 0 0 ? ? 0 0 0 7 Rhynchocephalia 0 0 0 0 0 0 1 0 8 Squamata 0 0 0 0&1 0 0 1 0 9 Rhynchosauria 0 0 0 1 0 0 1 0 1 0 Prolacertiformes 0 0 0 0 0 0 0&1 0 1 1 Trilophosaurus 0 0 0 0 0 0 1 0 1 2 Choristodera ? 0 0 1 0 0 0 0 1 3 Archosauriformes 0&1 0 0 0&1 0&1 0 0&1 0 1 4 Claud iosaurus 0 0 1 0 0 0 0 0 ? 1 5 Oactylosaurus ? 0 1 0 1 ? 0 0 1 6 Serpiano-Neustico ? 0 1 0 1 ? 0 0 1 7 Simosaurus 2 0 1 0 0 1 0 1 1 8 Nothosaurus 2 0 0&1 1 0 1 0 1 1 9 Lariosaurus ? 0 1 ? 0 ? 0 1 20 Corosaurus ? 0 0 ? 0 ? 1 1 2 1 Cymatosaurus ? 0 0 1 0 1 ? 0 9 22 Germanosaurus ? ? ? ? ? ? ? ? ? 23 Pistosaurus ? 0 0 ? 0 ? ? ? ? 24 Placodus 1 0 0 1 0 0 1 1 0 the plesiomorphic condition and the one seen in Cymatosaurus and Pistosaurus. Cymatosaurus was recoded for character 19(2&3) in view of an as yet undescribed species from the lower Mu- schelkalk of Thuringia that shows a sagittal crest (Rieppel & Werneburg, in prep.). The fact that the braincase (except for the basicranium in the un- described specimen from the lower Muschelkalk of Thuringia) is missing in all specimens of Cy- matosaurus available today resulted in recoding characters 31(0) and 32(1) for Cymatosaurus. At- tention is also drawn to the occiput of the speci- men bgr S 44/3 (Fig. 3B), which shows a distinct notch in the lower margin of the occipital expo- sure of the squamosal. A similar notch receives the distal end of the paroccipital process in a loose articulation in Corosaurus. Preservation of the basicranium in the undescribed specimen from the lower Muschelkalk of Thuringia also documents an akinetic palate for Cymatosaurus (character 41 [1]) in spite of the otherwise loose connection of the braincase with the dermatocranium and the reconstruction of the passage of the internal ca- rotid in this genus (character 47; see also Rieppel, 1994b). Characters for the postcranial skeleton of Cymatosaurus were coded and/or added on the assumption that Proneusticosaurus Volz, 1 902, is a junior synonym of the first genus (Sues, 1987; Rieppel & Hagdorn, 1996). In an initial PAUP analysis, all Sauropterygia were treated as ingroup taxa (presumed monophy- letic); the Captorhinidae, Testudines, Araeosceli- dia, Younginiformes, and Claudiosaurus were used as outgroup (paraphyletic). All other taxa were deleted from the analysis, rendering char- acters 2, 5, 24, 28, 34, 40, 53, 63, 66, 111, and 117 uninformative (ignored). All multistate char- acters were treated as unordered except for char- acter 27, which was ordered because presence of a lower temporal opening must logically precede the loss of the lower temporal arcade (see also Rieppel, 1994a). Heuristic search options includ- ed random stepwise addition and branch swapping (on minimal trees only) by tree bisection and re- RIEPPEL: REVISION OF CYMATOSAURUS 25 Table 3. Continued. 6 5 1 5 2 53 5 4 5 5 5 6 57 5 8 5 9 6 0 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 ? 0 0 0 0 0 3 Testudines 0 1 ? ? ? 9 ? 0 0&1 0&2 4 Araeoscelidia 0 1 0 0 0 0 0 0 0 0 5 Younginiformes 0 ? 0 0 0 0 0 0 0 6 Kuehneosauridae 0 ? 0 0 0 0 1 1 0 7 Rhynchocephalia 0 1 1 0 0 0 1 0&1 0 8 Squamata 0 1 1 0 0 0 1 0&2 9 Rhynchosauria 0 0 0 ? 0 0 1 0 1 0 Prolacertiformes 0 1 0 0 0 0 0&1 0&2 1 1 Trilophosaurus 0 ? 0 ? 0 0 1 1&2 1 2 Choristodera 0 1 0 0 0 0 0 1 1 3 Archosauriformes 0 1 0 0 0 0 0&1 0&1&2 1 4 Claudiosaurus 0 1 0 0 0 0 0 ? 0 1 5 Dactylosaurus 0 ? 0 0 0 0 1 0 1 6 Serpiano-Neustico 0 ? 0 0 0 0 1 0 1 7 Simosaurus 0 1 0 0 2 1 1 1 8 Nothosaurus 2 1 0 0 2 1 1 1 9 Lariosaurus 2 ? 0 0 2 1 1 20 Corosaurus 1 ? 0 0 1 1 0 2 1 Cymatosaurus 2 1 0 0 1 1 1 22 Germanosaurus ? ? 0 1 1 ? ? ? 23 Pistosaurus ? ? 0 0 1 1 1 1 24 Placodus 2 0 0 0 1 0 1 0 0 connection. One hundred replications yielded two MPTs with a TL of 283 steps, a CI of 0.675, and an RI of 0.702. The strict consensus tree of the two MPTs (Fig. 13) shows lack of resolution among outgroup taxa. Sauropterygian relation- ships are fully resolved, however, and differ sig- nificantly from previous results (Rieppel, 1994b). The emendation of the data matrix results in full resolution of the interrelationships of the genera Cymatosaurus, Lariosaurus, Nothosaurus, and Pistosaurus, which formed an unresolved poly- tomy in the previous analysis (Rieppel, 1994a, Fig. 67). Moreover, the analysis reveals paraphyly of the Eusauropterygia sensu Tschanz (1989), as it dramatically changes the position of pachypleu- rosaurs (see Fig. 13 and discussion below). Identical sauropterygian interrelationships re- sult from a more encompassing analysis that treats all 23 taxa in the analysis (see Table 3) as mono- phyletic ingroup (Reptilia), rooted on an all-0 an- cestor. All characters are informative. Heuristic search settings were the same as before, again with character 27 as the only ordered multistate character, with random stepwise addition, and with branch swapping (on minimal trees only) by tree bisection and reconnection. One hundred rep- lications yielded two MPTs, with a TL of 452 steps, a CI of 0.648, and an RI of 0.71 1. The strict consensus tree (Fig. 14) shows lack of resolution to be restricted to the interrelationships among ar- chosauromorph taxa; all other taxa are fully re- solved. Testudines remains the sister-group of the Sauropterygia, with the Lepidosauria as sister- group of the two. Interrelationships within the Sauropterygia are completely resolved, as was the case in the previous analysis using selected out- group taxa only. Placodus remains the sister-taxon of all other sauropterygians, the Eosauropterygia (Rieppel, 1994a), whereas the Eusauropterygia sensu Tschanz (1989) are, again, paraphyletic. In contrast to the earlier analysis, the new data basis shows the Eosauropterygia to subdivide into two major clades. The basal clade (of the ladderized cladogram in Fig. 14) comprises the genera (Co- 26 FIELDIANA: GEOLOGY Table 3. Continued. 7 6 1 6 2 6 3 64 65 6 6 67 68 69 70 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 ? 0 0 0 0 0 3 Testudines 1 0&1 0 0 0 0 0 0 0 4 Araeoscelidia 0 0 0 ? 0 0 0 0 0 5 Younginiformes 0 0 0 0 0 0 0 0 0 6 Kuehneosauridae 1 1 0 ? 1 0 0 0 1 7 Rhynchocephalia 0&1 0 1 0 0 0 0 0 0 8 Squamata 1 0 0&1 0 0 0 0 0 0&1 9 Rhynchosauria 0 0 0 ? 0 0 0 0 0&1 1 0 Prolacertiformes 0&1 0&1 0 ? 0 0 0 0 0 1 1 Trilophosaurus 0 0 0 ? 0 ? 0 0 0 1 2 Choristodera 1 0 0 1 0 0 0 0 0 1 3 Archosauriformes 0&1 0&1 0 0 1 0 0 0 0&1 1 4 Claudiosaurus 0 0 0 ? 0 0 0 0 0 1 5 Dactylosaurus 1 1 0 1 0 1 0 1 6 Serpiano-Neustico 1 1 0 1 0 1 0 1 7 Simosaurus 1 1 0 0 0 0 1 1 8 Nothosaurus 1 1 0 1 0 0&1 0 1 9 Lariosaurus 1 ? ? 0 1 0 1 0 20 Corosaurus 1 0 0 0 1 0 1 2 1 Cymatosaurus 1 ? 1 0 0 0 ? ? 22 Germanosaurus ? ? ? ? ? ? ? ? ? ? 23 Pistosaurus ? ? ? 1 0 0 1 0 ? 24 Placodus 1 1 1 0 0 1 0 0 0 1 rosaurus, (Cymatosaurus, Pistosaurus)), and it is the sister-group of a clade that includes pachy- pleurosaurs, Simosaurus, Germanosaurus, and the Nothosaurus-Lariosaurus clade. In contrast to previous results (Rieppel, 1994a), both Corosau- rus and pachypleurosaurs are nested within the Eusauropterygia sensu Tschanz (1989). The monophyletic pachypleurosaurs (Dactylosaurus and the Serpianosaurus—Neusticosaurus clade) form the sister-group of a nothosaurian clade that includes the sequential sister-taxa (Simosaurus, (Germanosaurus, (Nothosaurus, Lariosaurus))). Sauropterygian interrelationships remain un- changed in a tree one step longer than the two MPTs (TL = 453). A tree two steps longer (TL = 454) conserves the monophyly of pachypleu- rosaurs, of the Germanosaurus-Nothosaurus- Lariosaurus clade, and of the Corosaurus-Cy- matosaurus-Pistosaurus clade, but the three clades fall into an unresolved polytomy with Pla- codus. In a tree three steps longer (TL = 455), only the monophyly of the Corosaurus-Cymato- saurus-Pistosaurus and of the Germanosaurus- Nothosaurus-Lariosaurus clades is conserved be- yond the monophyly of the Sauropterygia. A tree four steps longer (TL = 456) retains monophyly of the Sauropterygia only. Bootstrap support val- ues (1,000 replications) are 100% for the mono- phyly of the Sauropterygia, 94% for the mono- phyly of pachypleurosaurs (Dactylosaurus and the Serpianosaurus-Neusticosaurus clade), 92% for the sister-group relationship of Nothosaurus and Lariosaurus, 60% for the monophyly of the Eo- sauropterygia, 5 1 % for the monophyly of the (Co- rosaurus, (Cymatosaurus, Pistosaurus)) clade, 56% for the (Simosaurus, (Germanosaurus, (No- thosaurus Lariosaurus))) clade, 53% for the (Ger- manosaurus, (Nothosaurus, Lariosaurus)) clade, and 53% for the sister-group relationship of Cy- matosaurus and Pistosaurus. The implementation of Deltran character op- timization will minimize the number of synapo- morphies diagnostic at any node that will subse- quently be lost again within that same clade. For RIEPPEL: REVISION OF CYMATOSAURUS 27 Table 3. Continued. 8 7 1 1 72 73 74 75 7 6 77 78 79 80 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 ? 0 0 0 0 3 Testudines 0 0 0 0 0 1 0 0 0 0 4 Araeoscelidia 0 0 0 0 0 0 0 0 0 0 5 Younginiformes 0 0 0 0 0&1 0&1 1 0 0 0 6 Kuehneosauridae ? 0 0 0 1 ? ? ? ? ? 7 Rhynchocephalia 0 0 0 0 1 1 1 0 0 0 8 Squamata 0 0 0 0 1 1 0&1 0 0 0 9 Rhynchosauria 0 0 0 0 0 1 1 0 0 0 1 0 Prolacertiformes 1 0 0 0 1 1 1 0 0 0 1 1 Trilophosaurus 1 0 0 0 ? 1 1 0 0 0 1 2 Choristodera 1 0 1 0 0 1 1 1 0 0 1 3 Archosauriformes 1 0 0&2 0 0&1 1 1 0 0 0 1 4 Claudiosaurus 1 0 0 0 1 1 1 0 0 0 1 5 Dactylosaurus 1 0 1 1 0 1 0 1 1 1 1 6 Serpiano-Neustico 1 1 1 1 0 1 0 1 1 0 1 7 Simosaurus 1 0 1 0 0 1 0 1 1 1 1 8 Nothosaurus 1 0&1 1 1 0&1 1 0&1 1 1 1 1 9 Lariosaurus 1 0&1 2 1 0 1 0 1 1 1 20 Corosaurus 1 0 1 0 1 1 1 1 0 1 2 1 Cymatosaurus ? 0 ? ? 0 1 ? ? ? ? 2 2 Germanosaurus ? ? ? ? ? 1 ? ? ? ? 23 Pistosaurus 1 0 ? ? ? 1 ? ? ? ? 24 Placodus 1 0 1 0 0 1 1 1 0 0 that reason, it will generally indicate synapo- morphic characters (character states) at a level of minimal inclusiveness (rather than maximal inclu- siveness, as an Acctran character optimization would). Taxa are here diagnosed on the basis of Deltran character optimization. The synapomor- phies linking Cymatosaurus with Pistosaurus are the following: 6(2) nasals strongly reduced or ab- sent (CI = 0.667); 8(1) nasals (always) separated by premaxilla-frontal contact (CI = 0.8); 16(2) frontal enters anteromedial margin of upper tem- poral fossa (CI = 0.714, reversed in some Cy- matosaurus); 17(1) parietal fused in their poste- rior part only (CI = 0.8); 19(3) parietal forming a sagittal crest (CI = 0.727, reversed in some Cy- matosaurus); 29(1) quadratojugal absent (CI = 0.667); 60(1) vertebrae platycoelous (CI = 0.7); 64(1) zygosphene-zygantrum articulation present (CI = 0.5). Unequivocal synapomorphies (out of a total of nine characters supporting the node) hared by Corosaurus and the Cymatosaurus-Pis- irus clade are the notch on the squamosal for articulation with the distal end of the paroccipital process (32[1]) and the distal expansion of the posterodorsal process of the scapula (85[1]). Un- der the new phylogenetic hypothesis of saurop- terygian interrelationships, the open occiput in Corosaurus, Cymatosaurus, and Pistosaurus (and by extension, in plesio- and pliosaurs) is a ple- siomorphic trait rather than a reversal. Unequivocal synapomorphies (CI = 1 ; out of a total of nine characters supporting the node) shared by pachypleurosaurs and the (Simosaurus (Germanosaurus (Nothosaurus, Lariosaurus))) clade are the clavicles which meet in an antero- medial suture (79[1]), and the strongly waisted coracoid (88[2]). Simosaurus shares with the No- thosauridae a total of 16 synapomorphies, among which are the following: the posteriorly displaced pineal foramen (18[1]), the broad dorsal wing of the epipterygoid (39[0]; unknown for Germano- saurus), the complex lateral relations of the ba- sioccipital tubers (42 [2]; unknown for Germano- saurus and Lariosaurus), the extension of the FIELDIANA: GEOLOGY Table 3. Continued. 9 8 1 82 83 84 85 8 6 | 8 7 88 89 90 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 7 0 7 0 1 0 0 0 3 Testudines 0 1 0 0 7 7 0 0 1 0 4 Araeoscelidia 0 1 0 0 7 0 1 0 0 0 5 Younginiformes 0 0&1 0 0 7 0 0 0 0 6 Kuehneosauridae ? 7 7 1 ? 0 0 0 0 7 Rhynchocephalia 0 1 0 0 ? 0 0 0 0 8 Squamata 0 1 0&1 0 ? 0 0 0 0 9 Rhynchosauria 0 1 0 0 ? 0 0 0&1 0 1 0 Prolacertiformes 0 0 7 0 ? 0 0 0 0 1 1 Trilophosaurus 0 1 0 0 ? 0 0 0 0 1 2 Choristodera 0 1 0 0 7 0 0 0 0 1 3 Archosauriformes 0 1 0 0 ? 0 0 0&1 0 1 4 Claudiosaurus 0 1 0 0 ? 0 0 0 0 1 5 Dactylosaurus 7 7 0 0 2 1 6 Serpiano-Neustico 0&1 2 0 0 2 1 7 Simosaurus 1 1 0 0 2 1 8 Nothosaurus 0&1 2 0 0 2 1 9 Lariosaurus 7 ? 0 0 2 20 Corosaurus 1 1 1 0 1 2 1 Cymatosaurus 7 7 7 7 7 7 0 7 7 7 2 2 Germanosaurus 7 7 ? 7 7 7 0 7 7 7 23 Pistosaurus 7 7 7 1 1 0 3 7 7 24 Ptacodus 1 1 1 0 ? 0 0 1 1 maxillary tooth row to a level below the upper temporal fossa (57 [2]; reversed in Germanosau- rus), the reduced posterior process on the ilium (99[2], unknown in Germanosaurus), and the con- cave ventral (medial) margin of the pubis (100[1], unknown in Germanosaurus). Synapomorphies of the Nothosauridae, shared by Germanosaurus and the Nothosaurinae (No- thosaurus and Lariosaurus), are the following: 3(1) snout constricted (CI = 0.333); 4(1) temporal region of skull strongly depressed (CI = 1); 11(1) reduced dorsal exposure of prefrontal (CI = 1); 23(2) jugal restricted to position behind orbit without entering its posterior margin (CI = 1; rarely reversed in individuals of Nothosaurus); 55(1) premaxillary and anterior dentary fangs present (CI = 0.5). The Nothosaurinae (Notho- saurus and Lariosaurus) finally share eight syn- apomorphies, that is, the fused frontals (14[1]), the strongly constricted parietal skull table (19[2]), the horizontal position of the supraoccip- ital (35[1]), the presence of an occipital crest (36[1]), the strongly elongated mandibular sym- physis (5 1 [2]), the presence of paired fangs in the maxilla (56[0]), the unconstricted vertebral centra (67[1]), and the absence of a distal expansion on the sacral ribs (74[1]). Several of these characters are convergent in Cymatosaurus. Phylogenetic Pattern and Stratigraphic Superposition With a more resolved cladogram of sauropter- ygian interrelationships at hand, a comparison of stratigraphic superposition (age rank) of taxa with their position in the cladogram (clade rank) be- comes possible. Clade rank (Fig. 15) was deter- mined following the method outlined by Norell and Novacek (1992). Calibration of age rank (Fig. 16) is here based on the stratigraphy of the Ger- manic Triassic (so, Rot, upper Buntsandstein; mu, lower Muschelkalk; mm, middle Muschelkalk; RIEPPEL: REVISION OF CYMATOSAURUS 29 Table 3. Continued. 10 9 1 9 2 93 94 9 5 9 6 9 7 98 9 9 1 00 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 0 0 0 0 0 3 Testudines 0 0 0 0 0&1 0&2 1 0 1&2 0 4 Araeoscelidia 0 0 0 0 0 0 0 0 0 5 Younginiformes 0 0 0 0 0&2 0 0&1 0 0 6 Kuehneosauridae 0 0 0 0 2 1 2 0 0 7 Rhynchocephalia 0 0 0 0 2 0 0 0 0 8 Squamata 0 0 0 0 0&2 1 0 0 0 9 Rhynchosauria 0 0 0 0 0 1 0 0 0 1 0 Prolacertiformes 0 0 0 0 0 1 1&2 0 0 1 1 Trilophosaurus 0 0 ? 0 0 1 0 0 0 1 2 Choristodera 0 0 0 0 0&2 1 2 0 0 1 3 Archosauriformes 0 0 0 0&1 0 1 0 0 0 1 4 Claudiosaurus 0 0 1 1 1 1 0 0 0 0 1 5 Dactylosaurus 0 1 0 1 0 0 0 1 3 0 1 6 Serpiano-Neustico 0 1 0 1 0&1 0&1 0 1&2 3 0&1 1 7 Simosaurus 0 1 0 1 1 1 1 2 2 1 1 8 Nothosaurus 0 1 0&1 0&1 1 0&1 0 2 2 1 1 9 Lariosaurus 0 1 1 1 1 1 0 2 3 0&1 20 Corosaurus 0 1 1 1 1 0 0 2 1 0 2 1 Cymatosaurus 0 0 0 0 0 0 0 ? ? 0 2 2 Germanosaurus ? ? ? ? ? ? ? ? ? ? 23 Pistosaurus 0 1 ? 1 1 1 1 2 0 ? 24 Placodus 0 1 1 1 1 0 1 2 1 0 mo, upper Muschelkalk). The boundary between Spathian (upper Scythian, upper Lower Triassic) and Anisian (lower Middle Triassic) corresponds to the boundary between Buntsandstein (so2) and Muschelkalk (mu,). The boundary between Ani- sian and Ladinian corresponds to the boundary between mo, and mo2 in the upper Muschelkalk. A full discussion of stratigraphic correlations for sauropterygians from the Germanic and Alpine Triassic can be found in Rieppel and Hagdorn (1996). Looking at the Sauropterygia as a whole (Fig. 16A), nonresolution is evident, that is, a distinct clumping of the fossil record in the upper Spathi- an (Rot) and lower Anisian (lower Muschelkalk). The earliest record for Placodus (clade rank 1), and indeed for Placodontia as a whole in Euro- pean epicontinental deposits (Rieppel, 1995b), is from the lower Gogolin Beds (basal mu,) in Up- per Silesia (Meyer, 1851b; Huene, 1905) and, thus, perhaps slightly younger than the occurrence of Corosaurus (clade rank 2) in the upper Scyth- ian of North America (Storrs, 1991, 1993a; the Alcova limestone that yielded Corosaurus is be- lieved to represent an "uppermost Lower Triassic or Scythian (Spathian) rock unit, or perhaps low- ermost middle Triassic or Anisian"; Storrs, 1991; p. 101). The first occurrence of Cymatosaurus is in the upper Buntsandstein (so2, Rot) of Ruders- dorf near Berlin. The first occurrence of Placodus is also slightly younger than that of pachypleu- rosaurs, which in the Germanic Triassic may reach back to the upper Buntsandstein (so2, Rot) (Dactylosaurus [clade rank 3]; see Rieppel & Lin, 1995). Unfortunately, the stratigraphic control over the occurrence of Keichousaurus in China is not as precise as the data available for the Mu- schelkalk fossils. The first occurrence of Notho- sauridae (age rank 5) again is in the lower Go- golin Beds (basal mu1) of Upper Silesia (Kunisch, 1888; Rieppel & Wild, in press) and, hence, dif- ferent from the age rank attributed to these taxa by Storrs (1993b, Fig. 5), who shows "Notho- sauridae" to appear later than Placodus and pa- 30 FIELDIANA: GEOLOGY Table 3. Continued. 11 101 102 1 03 104 105 1 06 1 07 1 08 1 09 1 10 1 Ancestor 0 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 0 0 0 0 0 3 Testudines 0 1 0 0 0 0 1 1 1 0 4 Araeoscelidia 0 0 0 0 0 0 0 0 0 0 5 Younginiformes 0 0 0 1 0 0 0 6 Kuehneosauridae 0 1 0 1 0 ? 0 7 Rhynchocephalia 0 1 0 1 0 1 0 8 Squamata 0 1 0 1 0 1 0 9 Rhynchosauria 0 0 0 1 0 1 0 1 0 Prolacertiformes 0 0&1 0 1 0 0 0 1 1 Trilophosaurus 0 0 0 1 0 0 0 1 2 Choristodera 0 0 0 1 1 ? 0 1 3 Archosauriformes 0 0 0 1&2 0&1 0 0 1 4 Claudiosaurus 0 0 0 1 1 0 0 1 5 Dactylosaurus 0 ? ? ? ? ? 0 1 6 Serpiano-Neustico 0&1 2 1 1 1 1 7 Simosaurus 0 2 1 1 1 1 8 Nothosaurus 0 2 1 1 1 1 9 Lariosaurus 1 2 1 1 1 20 Corosaurus 1 0 1 1 1 0 2 1 Cymatosaurus 1 0 1 1 ? ? 22 Germanosaurus ? ? ? ? ? ? ? ? ? ? 23 Pistosaurus ? ? ? 1 ? ? 9 ? ? 24 Placodus 0 1 1 0 1 1 1 1 0 chypleurosaurs to appear later than "Nothosauri- dae." Taxa that escape the clumping around the late Lower Triassic and early Middle Triassic are the late-appearing Simosaurus (upper Muschel- kalk, mo2; clade rank 4) and Lariosaurus (here considered to include Silvestrosaurus and Cere- siosaurus, and hence with a first occurrence at the Anisian-Ladinian boundary; clade rank 7). Pis- tosaurus is another late occurrence in the upper Muschelkalk (mo,) of Bayreuth. As noted by Storrs (1993a), these late occurrences highlight the incompleteness of the fossil record for the Sauropterygia. The late appearance of Simosau- rus, and its restriction to the Ladinian of the southern Germanic Basin and of the northern Alps, is particularly problematic, because cladistic analysis shows this taxon to be the sister-group to the Nothosauridae, with both Germanosaurus and Nothosaurus appearing in the basal Muschelkalk. Jaw fragments described as Hemilopas by Meyer (1851a) from the basal middle Muschelkalk could perhaps represent an early simosaurid, partially bridging the stratigraphic gap highlighted by cla- distic analysis (Rieppel, 1995a). Alternatively, the clade rank of Simosaurus might change following the study of Chinese material (Shingyisaurus Young, 1965). The clumping of sauropterygian taxa at the transition from the Lower to the Middle Triassic (Fig. 16A) appears to be an effect of sampling bias, as it correlates with marine transgressions that started in late Spathian times and persisted from early Anisian through Ladinian times and that induced the formation of the Rot (upper Low- er Triassic) and Muschelkalk (Middle Triassic) sediments in Europe (Hagdorn, 1991). The com- parison of age rank and clade rank in Sauropter- ygia presented in this study seems to highlight the early immigration of these taxa into the newly formed epicontinental sea, rather than the rapid and early diversification of the Sauropterygia within this emerging ecosystem. This conclusion is in accordance with the observation that all ear- liest occurrences of European taxa are in the east- RIEPPEL: REVISION OF CYMATOSAURUS 31 Table 3. Continued. 12 1 1 1 1 1 2 1 13 1 14 1 15 1 1 6 1 17 1 18 1 19 1 Ancestor 0 0 0 0 0 0 0 0 0 2 Captorhinidae 0 0 0 0 0 0 0 0 0 3 Testudines 0 0 0&1 1 0 1 1 0 ? 4 Araeoscelidia 0 0 0 0 0 0 1 0 5 Younginiformes 0 0 0 0 1 0 1 0 6 Kuehneosauridae ? ? ? ? ? ? ? ? ? 7 Rhynchocephalia 0 0&1 1 0 1 1 1 0 8 Squamata 0 1 1 0 1 1 1 ? 9 Rhynchosauria 1 0 1 0 1 1 ? 0 1 0 Prolacertiformes 0&1 0&1 1 0 1 0&1 1 0 1 1 Trilophosaurus 1 0 1 0 1 1 ? ? 1 2 Choristodera 1 0 1 0 1 1 ? ? 1 3 Archosauriformes 1 0&1 1 0 1 1 1 0 1 4 Claudiosaurus 0 0 0 0 0 0 ? 0 1 5 Dactylosaurus ? ? ? ? ? ? ? 0 0 1 6 Serpiano-Neustico 0 0 1 1 2 0 0 0 0 1 7 Simosaurus 0 0 1 1 1 0 0 0 1 1 8 Nothosaurus 0 0 1 1 1 0 0 0 1 1 9 Lariosaurus 0 0 1 1 0 0 0 0 0 20 Corosaurus 0 0 1 1 1 ? ? 0 1 2 1 Cymatosaurus ? ? ? ? ? ? ? 0 0 22 Germanosaurus ? ? ? ? ? ? ? 0 ? 23 Pistosaurus ? ? ? ? ? ? ? 0 ? 24 Placodus 0 0 1 1 2 0 0 0 0 em part of the Germanic Basin, which is believed to have been connected to the Paleotethys through the East Carpathian gate (Kozur, 1974; Hagdorn, 1985; Urlichs & Mundlos, 1985), and also with the fact that some sauropterygians with low clade rank occur in the late Lower Triassic or early Mid- dle Triassic outside Europe (Corosaurus in the western United States, and Placodontia and Eu- sauropterygia in Israel and China; Storrs, 1991; Brotzen, 1957; Young, 1959, 1960, 1965, 1978). This does not exclude the possibility that some sauropterygian taxa originated in the western Tethyan province, such as nothosaurian subclades (Lariosaurus). Analysis of pachypleurosaurs in isolation, how- ever, yields a different picture altogether (Fig. 16B, based on a comprehensive review of the phylogenetic interrelationships of the group; Rieppel & Lin, 1995). Clade rank 1 is assigned to the Chinese genus Keichousaurus, whose exact tratigraphic provenience within the Middle (or pper Lower?) Triassic is not known. Clade rank 2 is assigned to Dactylosaurus from the lower- most Muschelkalk, perhaps upper Buntsandstein (Rot). Anarosaurus from the uppermost lower Muschelkalk and from the basal middle Muschel- kalk is assigned clade rank 3. Serpianosaurus from the Anisian-Ladinian boundary ranks fourth in the cladogram and is followed in time by Neus- ticosaurus with clade rank 5. For pachypleuro- saurs at least, there exists a high degree of cor- relation between phylogenetic pattern and strati- graphic superposition, suggesting an eastern Teth- yan origin of the clade, and a diversification of the clade within the western Tethyan province. For the Nothosauridae, the two basal clades ranking 1 (Germanosaurus) and 2 (Nothosaurus) both appear in the lowermost Muschelkalk of Up- per Silesia. The late occurrence of Lariosaurus s.s. seems to point to a significant gap in the fossil record, which is partly bridged by the synonymy of the genera "Silvestrosaurus" and "Ceresiosau- rus" (solid dots in Fig. 16C) with Lariosaurus. Revision of the monophyletic clade including FIELDIANA: GEOLOGY "Silvestrosaurus,, (Anisian-Ladinian boundary), "Ceresiosaurus" (early Ladinian), and Lariosau- rus (middle to late Ladinian) at the alpha taxo- nomic level must precede the analysis of phylo- genetic interrelationships among its terminal taxa. Acknowledgments A number of colleagues granted generous ac- cess to the collection in their care, making the completion of this study possible. These are H. U. Schliiter, Bundesanstalt fur Geowissenschaften und Rohstoffe, Berlin; H. Haubold, Institut fur Geowissenschaften, Martin-Luther-Universitat, Halle/Saale; G. Kaufmann, Fachbereich Geowis- senschaften, Philipps Universitat, Marburg/Lahn; R. Werneburg, Naturhistorisches Museum Schloss Bertholdsburg, Schleusingen; G. Hock, Naturhis- torisches Museum, Wien; and R. Wild, Staatliches Museum fur Naturkunde, Stuttgart. Dr. G. Hock kindly provided the photograph of Germanosau- rus shown in Figure 10. H.-D. Sues and H. Hag- dorn critically read an earlier version of this paper, offering much helpful advice and criticism. This study was supported by NSF grants DEB- 9220540 and DEB-94 19675. Literature Cited Alafont, L. S., and J. L. Sanz. 1996. Un nuevo Sau- ropterigio (Reptilia) en el Triasico de la Sierra de Pra- des (Tarragona). 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Lariosaurus buzzii n. sp. from the Middle Triassic of Monte San Giorgio (Switzerland), with comments on the classification of nothosaurs. Pa- laeontographica, A, 208: 153-179. Urlichs, M., and R. Mundlos. 1985. Immigration of cephalopods into the Germanic Muschelkalk Basin and its influence on their suture line, pp. 221-236. In Bayer, U., and A. Seilacher, eds., Sedimentary and Evolutionary Cycles. Springer- Verlag, Heidelberg. Volz, W. 1902. Proneusticosaurus, eine neue Saurop- terygiergattung aus dem untersten Muschelkalk Ob- erschlesiens. Palaeontographica, 49: 121-164. Young, C.-C. 1959. On a new Nothosauria from the Lower Triassic Beds of Kwangsi. Vertebrata Pal- Asiatica, 3: 73-78. 1960. New localities of sauropterygians in China. Vertebrata PalAsiatica, 3: 73-78. . 1965. On the new nothosaurs from Hupeh and Kweichou, China. Vertebrata PalAsiatica, 9: 337-356. -. 1978. A nothosaur from Lu-hsi County, Yun- nan Province, Vertebrata PalAsiatica, 16: 222-224. Appendix The characters listed below are based on the data used previously in the analysis of the phy- logenetic interrelationships of Simosaurus (Riep- pel, 1994a). The data matrix relies heavily on the work of Gauthier et al. (1988), further augmented by the addition of characters taken from Evans (1988) and Storrs (1991, 1993b). Additional ref- erences pertaining to the coding of non-saurop- terygian taxa can be found in Rieppel (1994a). Coding for the postcranium of Cymatosaurus is based on the assumption that Proneusticosaurus Volz, 1902, is a subjective junior synonym of Cy- matosaurus Fritsch, 1894 (Rieppel & Hagdorn, 1996). 1. Premaxillae small (0) or large (1), forming most of snout in front of external nares. 2. Premaxilla without (0) or with (1) postnarial process, excluding maxilla from posterior margin of external naris. 3. Snout unconstricted (0) or constricted (1). 4. temporal region of skull relatively high (0) or strongly depressed (1). 5. Nasals shorter (0) or longer (1) than fron- tal(s). 6. Nasals not reduced (0), somewhat reduced (1), or strongly reduced or absent (2). 7. Nasals do (0) or do not (1) enter external naris. 8. Nasals meet in dorsomedial suture (0) or are separated from one another by nasal processes of the premaxillae extending back to the frontal bone(s) (1). 9. The lacrimal is present and enters the exter- nal naris (0) or remains excluded from the exter- nal naris by a contact of maxilla and nasal ( 1 ), or the lacrimal is absent (2). 10. The prefrontal and postfrontal are separated by the frontal along the dorsal margin of the orbit (0), or a contact of prefrontal and postfrontal ex- cludes the frontal from the dorsal margin of the orbit (1). 11. Dorsal exposure of prefrontal large (0) or reduced (1). 12. Preorbital and postorbital region of skull: of subequal length (0), preorbital region distinctly longer than postorbital region (1), postorbital re- gion distinctly longer (2). 13. Upper temporal fossa absent (0), present and subequal in size or slightly larger than the orbit (1), present and distinctly larger than orbit (2), or present and distinctly smaller than orbit (3). 14. Frontal(s) paired (0) or fused (1) in the adult. 15. Frontal(s) without (0) or with (1) distinct posterolateral processes. 16. Frontal widely separated from the upper temporal fossa (0), narrowly approaches the upper temporal fossa (1), or enters the anteromedial margin of the upper temporal fossa (2). 17. Parietal(s) paired (0), fused in their posterior part only (1), or fully fused (2) in adult. 18. Pineal foramen close to the middle of the skull table (0), is displaced posteriorly ( 1 ), is dis- placed anteriorly (2), or is absent (3). 19. Parietal skull table broad (0), weakly con- stricted (1), strongly constricted (at least posteri- orly) (2), or forming a sagittal crest (3). 20. Postparietals present (0) or absent (1). 21. Tabular present (0) or absent (1). 22. Supratemporals present (0) or absent (1). RIEPPEL: REVISION OF CYMATOSAURUS 35 23. The jugal extends anteriorly along the ven- tral margin of the orbit (0), is restricted to a po- sition behind the orbit but enters the latter's pos- terior margin (1), or is restricted to a position be- hind the orbit without reaching the latter's poste- rior margin (2). 24. The jugal extends backward no farther than to the middle of the cheek region (0), or nearly to the posterior end of the skull (1). 25. The jugal remains excluded from (0) or en- ters (1) the upper temporal arch. 26. Postfrontal large and plate-like (0), with dis- tinct lateral process overlapping the dorsal tip of the postorbital (1), or postfrontal with reduced lat- eral process and hence more of an elongate shape (2). 27. Lower temporal fossa absent (0), present and closed ventrally (1), or present but open ven- trally (2). 28. Squamosal descends to (0) or remains broadly separated from (1) ventral margin of skull. 29. Quadratojugal present (0) or absent (1). 30. Quandratojugal with (0) or without (1) an- terior process. 31. Occiput with paroccipital process forming the lower margin of the posttemporal fossa and extending laterally (0), paroccipital processes trending posteriorly (1), or occiput plate-like with no distinct paroccipital process and with strongly reduced posttemporal fossae (2). 32. Squamosal without (0) or with (1) distinct notch to receive distal tip of paroccipital process. 33. Mandibular articulations approximately at level with occipital condyle (0), displaced to a level distinctly behind occipital condyle (1), or positioned anterior to the occipital condyle (2). 34. Exoccipitals do (0) or do not (1) meet dorsal to the basioccipital condyle. 35. Supraoccipital exposed more or less verti- cally on occiput (0) or exposed more or less hor- izontally at posterior end of parietal skull table (1). 36. Occipital crest absent (0) or present (1). 37. Quadrate with straight posterior margin (0) or quadrate shaft deeply excavated (concave) pos- teriorly (1). 38. Quadrate covered by squamosal and quadra- tojugal in lateral view (0), or quadrate exposed in lateral view (1). 39. Dorsal wing of epipterygoid broad (0) or narrow (1). 40. Lateral conch on quadrate absent (0) or pres- ent (1). 41. Palate kinetic (0) or akinetic (1). 42. Basioccipital tubera free (0) or in complex relation to the pterygoid, as they extend ventrally (1) or laterally (2). 43. Suborbital fenestra absent (0) or present (1). 44. Pterygoid flanges well developed (0) or strongly reduced (1). 45. Premaxillae enter internal naris (0) or are excluded (1). 46. Ectopterygoid present (0) or absent (1). 47. Internal carotid passage enters basicranium (0) or quadrate ramus of pterygoid (1). 48. Retroarticular process of lower jaw absent (0) or present (1). 49. Distinct coronoid process of lower jaw ab- sent (0) or present (1). 50. Surangular without (0) or with (1) strongly projecting lateral ridge defining the insertion area for superficial adductor muscle fibers on the lat- eral surface of the lower jaw. 51. Mandibular symphysis short (0), somewhat enforced (1), or elongated and "scoop" -like (2). 52. Splenial bone enters the mandibular sym- physis (0) or remains excluded therefrom (1). 53. Teeth set in shallow or deep sockets (0) or superficially attached to bone (1). 54. Anterior (premaxillary and dentary) teeth upright (0) or strongly procumbent (1). 55. Premaxillary and anterior dentary fangs ab- sent (0) or present (1). 56. One or two caniniform teeth present (0) or absent (1) on maxilla. 57. The maxillary tooth row is restricted to a level in front of the posterior margin of the orbit (0), or it extends backward to a level below the posterior corner of the orbit and/or the anterior corner of the upper temporal fossa (1), or it ex- tends backward to a level below the anterior one third to one half of the upper temporal fossa (2). 58. Teeth on pterygoid flange present (0) or ab- sent (1). 59. Vertebrae notochordal (0) or non-notochord- al (1). 60. Vertebrae amphicoelous (0), platycoelous (1), or other (2). 61. Dorsal intercentra present (0) or absent (1). 36 FIELDIANA: GEOLOGY 62. Cervical intercentra present (0) or absent (1). 63. Cervical centra rounded (0) or keeled (1) ventrally. 64. Zygosphene-zygantrum articulation absent (0) or present (1). 65. Sutural facets receiving the pedicels of the neural arch on the dorsal surface of the centrum in the dorsal region are narrow (0) or expanded into a cruciform or "butterfly-shaped" platform (1). 66. Transverse processes of neural arches of the dorsal region relatively short (0) or distinctly elongated (1). 67. Vertebral centrum distinctly constricted in ventral view (0) or with parallel lateral edges (1). 68. Distal end of transverse processes of dorsal vertebrae not increasing in diameter (0) or dis- tinctly thickened (1). 69. Zygapophyseal pachyostosis absent (0) or present (1). 70. Prezygapophyses and postzygapophyses do not (0) or do (1) show an anteroposterior trend of increasing inclination within the dorsal and sacral region. 71. Cervical ribs without (0) or with (1) a dis- tinct free anterior process. 72. Pachyostosis of dorsal ribs absent (0) or present (1). 73. The number of sacral ribs is two (0), three (1), or four or more (2). 74. Sacral ribs with (0) or without (1) distinct expansion of distal head. 75. Sacral (and caudal) ribs or transverse pro- cesses sutured (0) or fused (1) to their respective centrum. 76. Cleithrum present (0) or absent (1). 77. Clavicles broad (0) or narrow (1) medially. 78. Clavicles positioned dorsally (0) or anter- oventrally (1) to the interclavicle. 79. Clavicles do not meet in front of the inter- clavicle (0) or meet in an interdigitating antero- medial suture (1). 80. Clavicles without (0) or with (1) anterolat- erally expanded corners. 81. Clavicle applied to the anterior (lateral) (0) or to the medial (1) surface of scapula. 82. Interclavicle rhomboidal (0) or T-shaped (1). 83. Posterior process on (T-shaped) interclavicle elongate (0), short (1), or rudimentary or absent (2). 84. Scapula represented by a broad blade of bone (0) or with a constriction separating a ventral glenoidal portion from a posteriorly directed dor- sal wing (1). 85. The dorsal wing or process of the eosaurop- terygian scapula tapers to a blunt tip (0) or is ven- trally expanded at its posterior end (1). 86. Supraglenoid buttress present (0) or absent (1). 87. One (0) or two (1) coracoid ossifications. 88. Coracoid of rounded contours (0), slightly waisted (1), strongly waisted (2), or with expand- ed medial symphysis (3). 89. Coracoid foramen enclosed by coracoid os- sification (0) or between coracoid and scapula (1). 90. Pectoral fenestration absent (0) or present (1). 91. Limbs short and stout (0) or long and slen- der (1). 92. Humerus rather straight (0) or "curved" (1). 93. Deltopectoral crest well developed (0) or re- duced (1). 94. Insertional crest for latissimus dorsi muscle prominent (0) or reduced (1). 95. Humerus with prominent (0) or reduced (1) epicondyles. 96. The ectepicondylar groove is open and notched anteriorly (0), open without anterior notch (1), or closed (2) (i.e., ectepicondylar fo- ramen present). 97. Entepicondylar foramen present (0) or ab- sent (1). 98. Radius shorter than ulna (0), longer than ulna (1), or approximately of the same length (2). 99. Iliac blade well developed (0), reduced but projecting beyond level of posterior margin of ac- etabular portion of ilium ( 1 ), reduced and no lon- ger projecting beyond posterior margin of acetab- ular portion of ilium (2), or absent (i.e., reduced to simple dorsal stub) (3). 100. Pubis with convex (0) or with concave (1) ventral (medial) margin. 101. Obturator foramen closed (0) or open (1) in adult. 102. Thyroid fenestra absent (0) or present (1). 103. Acetabulum oval (0) or circular (1). 104. Femoral shaft stout and straight (0) or slen- der and sigmoidally curved (1). RIEPPEL: REVISION OF CYMATOSAURUS 37 105. Internal trochanter well developed (0) or re- duced (1). 106. Intertrochanteric fossa deep (0), distinct but reduced (1), or rudimentary or absent (2). 107. Distal femoral condyles prominent (0) or not projecting markedly beyond shaft (1). 108. Anterior femoral condyle relative to poste- rior condyle larger and extending farther distally (0) or smaller/equisized and of subequal extent distally (1). 109. The perforating artery passes between as- tragalus and calcaneum (0) or between the distal heads of tibia and fibula proximal to the astragalus (1). 110. Astragalus without (0) or with (1) a proxi- mal concavity. 111. Calcaneal tuber absent (0) or present (1). 1 12. Foot short and broad (0) or long and slender (1). 113. Distal tarsal 1 present (0) or absent (1). 114. Distal tarsal 5 present (0) or absent (1). 115. Total number of tarsal ossifications four or more (0), three (1), or two (2). 1 16. Metatarsal 5 long and slender (0) or distinct- ly shorter than the other metatarsals and with a broad base (1). 117. Metatarsal 5 straight (0) or "hooked" (1). 118. Mineralized sternum absent (0) or present (1). 119. The medial gastral rib element always only has a single lateral process (0) or may have a two- pronged lateral process (1). 38 FIELDIANA: GEOLOGY A Selected Listing of Other Fieldiana: Geology Titles Available Status of the Pachypleurosauroid Psilotrachelosaurus toeplitschi Nopcsa (Reptilia, Sauropterygia), from the Middle Triassic of Austria. By Olivier Rieppel. Fieldiana: Geology, n.s., no. 27, 1993. 17 pages, 9 illus. Publication 1448, $10.00 Osteology of Simosaurus gaillardoti and the Relationships of Stem-Group Sauropterygia. By Olivier Rieppel. Fieldiana: Geology, n.s., no. 28, 1994. 85 pages, 71 illus. Publication 1462, $18.00 Revised Phylogeny and Functional Interpretation of the Edrioasteroidea Based on New Taxa from the Early and Middle Ordovician of Western Utah. By Thomas E. Guensburg and James Sprinkle. Field- iana: Geology, n.s., no. 29, 1994. 43 pages, 37 illus. Publication 1463, $12.00 Giant Short-Faced Bear {Arctodus simus yukonensis) Remains from Fulton County, Northern Indiana. By Ronald L. Richards and William D. Turnbull. Fieldiana: Geology, n.s., no. 30, 1995. 34 pages, 20 illus. Publication 1465, $10.00 The Genus Placodus: Systematics, Morphology, Paleobiogeography, and Paleobiology. By Olivier Riep- pel. Fieldiana: Geology, n.s., no. 31, 1995. 44 pages, 47 illus. Publication 1472, $12.00 Pachypleurosaurs (Reptilia: Sauropterygia) from the Lower Muschelkalk, and a Review of the Pachy- pleurosauroidea. By Olivier Rieppel and Lin Kebang. Fieldiana: Geology, n.s., no. 32, 1995. 44 pages, 28 illus. Publication 1473, $12.00 Order by publication number and/or ask for a free copy of our price list. All orders must be prepaid. Illinois residents add current destination tax. All foreign orders are payable in U.S. dollar-checks drawn on any U.S. bank or the U.S. subsidiary of any foreign bank. Prices and terms subject to change without notice. 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