Gecatogomphius kavejevi

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Gecatogomphius kavejevi


Gecatogomphius kavejevi is a multiple-tooth-rowed, moradisaurine captorhinid from the western forelands of the Ural Mountains in Russia. It is as yet the best known captorhinid from eurasia and the only recognized species of the genus.

Contents

Scientific History

G. kavejevi was discovered in 1955 by the Soviet geologist M. S. Kaveev who found a fragment of a lower jaw at the bank of the Vjatka River in Kirov District. Subsequently this bone was sent to the Academy of Science of the USSR. In 1957 it has been named and published. Since then only one further remain of G. kavejevi, a single fragmentary maxillary tooth plate, came to light.

Description

The dentary is about 8 cm in length. Its lateral wall is sculptured with an irregular pattern of long and deep groves as seen in many other captorhinids. Medially it is widened to form the typical moradisaurine tooth plate. In its anteriormost portion the dentary shows tree caniniform teeth being as twice as large than the teeth of the tooth plate. An alveola at the tip of the bone indicates the former presence of a fourth caniniform. The tooth plate bears more than 40 bulbous teeth arranged in five rows. Similar to Labidosaurikos the teeth of two adjacent rows each alternate and show more or less pronounced wear facets below the apex. An important particularity in G. kavejevi is that the jaw bears signs of resorption pits which is the only occurence of such a feature in moradisaurines so far.
The fragment of the maxillary tooth plate also bears five rows of teeth, showing a wear pattern similar to that of the teeth on the dentary.

Phylogeny

Despite the sparseness of the material preserved G. kavejevi is clearly a moradisaurine, i.e. a member of the most derived clade of the family. A close relationship to the North American representative Kahneria seltina has been postulated, however, since the establishment of modern cladistic methods the latter never was included in relevant analyses.

Some facts


Gecatogomphius kavejevi Vjushkov & Chudinov 1957

Family: Captorhinidae

Etymology of genus: "hundreds of cheek teeth"

Etymology of species: named after the Soviet geologist M.S. Kaveev

Paleogeography: Foreland Basin of the Urals, northeastern Pangaea

Locality: banks of Vyatka River, Kirov District, western Russia

Horizon: Belebei Formation

Synonyms: Everett C. Olson (1962) used the western transcription Hecatogomphius in his translation of Vjushkov & Chudinov's (1957) original description of this species. Since then this genus name was used numerous times by non-russian authors.

Stratigraphic Range: Upper Permian: Kazanian*

Ivakhnenko (1990) assigned the horizon of provenance of Gecatogomphius to the Ocher assemblage, a unit of russian non-marine vertebrate biostratigraphy. In Lucas (2006) this assamblage is correlated with the Kazanian stage of global stratigraphy.

References

DODICK, J.T. and MODESTO, S.P. (1995): The Cranial Anatomy of the Captorhinid Reptile Labidosaurikos meachami from the Lower Permian of Oklahoma. Palaeontology 38 (3): 687-711
IVAKHNENKO, M.F. (1990): Early Permian Elements of Faunal Assemblages of Tetrapods from Eastern Europe [Раннепермские элементы фаунистических комплексов тетрапод Восточной Европы]. Paleontologicheskii Zhurnal 1990 (2): 102-111 [russian]
LUCAS, S.G. (2006): Global Permian tetrapod biostratigraphy and biochronology. pp. 65-93 in SPENCER G. LUCAS et al. (eds.): Non-Marine Permian Biostratigraphy and Biochronology. Geological Society, London, Special Publications, vol. 265. The Geological Society, London
OLSON, E.C. (1962): Late Permian Terrestrial Vertebrates, U.S.A. and U.S.S.R. Transactions of the American Philosophical Society, ns 52 (2): 1-224
VJUSHKOV, B.P. and CHUDINOV, P.K. (1957): Discovery of a Captorhinid in the Upper Permian of the USSR [Открытие Kaпторинид в верхней Перми CCCP]. Doklady Akadademii Nauk SSSR 112 (3): 523-526 [russian]


Credits

--Zidane 10:09, 25 May 2008 (PDT)

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