Friday, July 30, 2010

Procerosaurus and Macroscelosaurus- two Tanystropheus

Tanystropheus actually has an extensive and complicated history as a theropod, as do most of its synonyms.  We deal with two today, and note the synonymy and distribution lists in this entry don't cover remains besides those referred to "Macroscelosaurus" and Procerosaurus.  Btw, If anyone has Wild's 1973 redescription of Tanystropheus or his 1971 thesis on the same topic, I'd happily accept them. ;)

Tanystropheus Meyer, 1852
= "Macroscelosaurus" Muenster vide Meyer, 1852
= Procerosaurus Huene, 1902
T. conspicuus Meyer, 1852
= "Macroscelosaurus" Muenster vide Meyer, 1852
= Procerosaurus cruralis Huene, 1902
= "Macroscelosaurus" conspicuus (Meyer, 1852) Kuhn, 1937
Anisian, Middle Triassic
Upper Muschelkalk, Germany
- (material of "Macroscelosaurus") cervical vertebrae
Referred- (holotype of Procerosaurus cruralis) incomplete femur (~415 mm) (Huene, 1902)
Comments- In the original desciption of Tanystropheus, Meyer (1852; sometimes cited as 1847 to/or 1855) stated that Muenster thought the type cervical vertebrae were reptilian limb bones and had named them Macroscelosaurus. No species name was given, and references to "Macroscelosaurus janseni" are misspellings of the therapsid Macroscelesaurus janseni (inappropriately renamed Haughtoniscus by Kuhn, who thought the name was too similar to "Macroscelosaurus"). Kuhn (1934) used "Macroscelosaurus" as a senior synonym of Tanystropheus, citing a "Muenster, 1834" reference which subsequent authors have not been able to verify. 1830 is another year that has often been cited, though Wild (1976) stated that a search of all known works of Muenster had proved fruitless. Wild (1975, 1976) noted that since "Macroscelosaurus" was first published as a junior synonym, it is invalid and petitioned the ICZN to have it officially suppressed. This was approved by the ICZN in 1981 (Melville, 1981). Huene (e.g. 1902, 1908) listed "Macroscelosaurus" as a junior synonym of Tanystropheus in Coeluridae. Piveteau (1955) used "Macroscelosaurus" as a valid genus of tanystropheid non-synonymous with Tanystropheus, which is not possible as they are based on the same material. Similarly, Kuhn's (1935) Macroscelosauridae is an objective junior synonym of Tanystropheidae, even if "Macroscelosaurus" were the valid name.

Holotype femur of Procerosaurus cruralis in posterolateral(?) view, after Huene, 1902.
Procerosaurus cruralis was described by Huene (1902) as a eusuchian most similar to gavials, though in a rather confusing paragraph which also states the lack of a fourth trochanter seems to prove it is dinosaurian. He ironically stated some similarity could exist with Tanystropheus longicollis (now recognized as coelophysid material, in this case AMNH 2704) based on Cope's description, but examination of the specimen itself showed they weren't similar after all. In 1910, Huene stated it was similar to Saltopus and that he never regarded it as crocodilian (though he did not synonymize it with Tanystropheus yet, contra Olshevsky, 1991). Huene later (1914a) placed Procerosaurus in parentheses under Tanystropheus, perhaps indicating he had synonymized them by this time, and included both as a central coelurosaur lineage within Podokesauridae. In the same year (1914b), he described additional supposed coelurosaur femora from the slightly younger Lower Muschelkalk as being most similar to Procerosaurus. General reference works such as Zittel (1927), Romer (1956) and Kuhn (1969) also used it as a synonym of Tanystropheus, which was confirmed by Wild's (1973) osteology of the latter genus. It was synonymized with T. conspicuus by Wild, probably due to provenence. Notably, Huene's favorable comparisons to theropods used taxa which are no longer thought to be dinosaurian (Saltopus, the Lower Muschelkalk femora), while his comparison to Tanystropheus was based on a theropod femur as no appendicular elements were yet referred to that genus. The femur of Procerosaurus differs from Triassic theropods in lacking a fourth trochanter and an ectocondylar tuber. While Olshevsky stated it has sometimes been classified as an ornithischian, this seems to only be true of Procerosaurus Fritsch, 1905. This was a new genus for Iguanodon exogirarum, a Cretaceous taxon named by Fritsch in 1878 for a possible tibia. Because Fritsch's genus was preoccupied by Huene's, Olshevsky renamed it Ponerosteus in 2000.

References- Meyer, 1852. Die saurier des Muschelkalkes mit ruecksicht auf die saurier aus Buntem Sanstein und Keuper. in Zur fauna der Vorwelt, zweite Abteilung 42. 167 pp.

Fritsch, 1878. Die Reptilien und Fische der böhmischen Kreideformation. Prague. 46 pp.

Huene, 1902. Übersicht über die Reptilien der Trias [Review of the Reptilia of the Triassic]. Geologische und Paläontologische Abhandlungen. 6, 1-84.

Fritsch, 1905. Synopsis der Saurier der böhm. Kreideformation [Synopsis of the saurians of the Bohemian Cretaceous formation]. Sitzungsberichte der königlich-böhmischen Gesellschaft der Wissenschaften, II Classe. 1905(8), 1-7.

Huene, 1908. Die Dinosaurier der Europäischen Triasformation mit berücksichtigung der Ausseuropäischen vorkommnisse [The dinosaurs of the European Triassic formations with consideration of occurrences outside Europe]. Geologische und Palaeontologische Abhandlungen. Supplement 1(1), 1-419.

Huene, 1910. Ein primitiver Dinosaurier aus der mittleren Trias von Elgin. Geologische und Paläontologische Abhandlungen, 8, 315-322.

Huene, 1914a. Das natürliche System der Saurischia [The systematics of the Saurischia]. Centralblatt für Mineralogie, Geologie und Paläontologie. 1914, 154-158.

Huene, 1914b. Coelurosaurier Reste aus dem Unteren Muschelkalk. Centralblatt ftir Mineralogie, Geologie und Palaontologie. 1914, 670-672.

Zittel, 1927. Textbook of Paleontology. Macmillan Co. Limited. Vol. I, 839 pp.

Kuhn, 1934. Sauropterygia. Fossilium Catalogus I: Animalia. 69, 127 pp.

Kuhn, 1935. Rhynchocephalia (Eosuchia). Fossilium Catalogus I: Animalia. 71, 38 pp.

Kuhn, 1937. Die fossilen Reptilien. Berlin: Gebrueder Borntrager. 121 pp.

Piveteau, 1955. Traite de paleontologie. V. Amphibiens, reptiles, oiseaux. Masson, Paris. 1113 pp.

Romer, 1956. Osteology of the Reptiles. University of Chicago Press. 772 pp.

Kuhn, 1969. Proganosauria, Bolosauria, Placodontia, Araeoscelidia, Trilophosauria, Weigeltisauria, Millerosauria, Rhynchocephalia, Protorosauria. Handbuch der Palahoerpetologie. 9, 74 pp.

Wild, 1973. Die Triasfauna der Tessiner Kalkalpen. XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). Schweizerische Palaontologische Abhandlungen. 95, 1-162.

Wild, 1975. Tanystropheus H. v. Meyer, 1855 (Reptilia): Request for conservation under the plenary powers. Z.N.(S.) 2084. Bulletin of Zoological Nomenclature.32, 124-126.

Wild, 1976. Tanystropheus H. von Meyer, [1852] (Reptilia): Revised request for conservation under the plenary powers. Z.N.(S.) 2084. Bulletin of Zoological Nomenclature. 33, 124-126.

Melville, 1981. Opinion 1186. Tanystropheus H. von Meyer, [1852] (Reptilia) conserved. Bulletin of Zoological Nomenclature. 38(3), 188-190.

Olshevsky, 1991. A Revision of the Parainfraclass Archosauria Cope, 1869, Excluding the Advanced Crocodylia. Mesozoic Meanderings. 2, 196 pp.

Olshevsky, 2000. An Annotated Checklist of Dinosaur Species by Continent. Mesozoic Meanderings. 3, 157 pp.

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