| Dvinosaurus Temporal range: Middle - Late Permian
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|---|---|
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| Life restoration of Dvinosaurus egregius | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | †Temnospondyli |
| Suborder: | †Dvinosauria |
| Superfamily: | †Dvinosauroidea |
| Family: | †Dvinosauridae Amalitzkii, 1921 |
| Genus: | †Dvinosaurus Amalitzky, 1921 |
| Type species | |
| †Dvinosaurus primus Amalitzkii, 1921
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| Other species | |
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Dvinosaurus is an extinct genus of amphibious temnospondyls localized to regions of western and central Russia during the middle and late Permian, approximately 265-254 million years ago.[2] Its discovery was first noted in 1921 by Russian paleontologist Vladimir Prokhorovich Amalitskii in a posthumously published paper that documents the findings of a site in Russia's Arkhangelsk District. [3] Its name is derived from the proximity of this site to the Northern Dvina River.[4]
Dvinosaurus is thought to have been a gill-breathing, fully-aquatic tetrapod, characterized by a large, triangular head, short limbs, and a long powerful tail.[3] A typical individual could grow to be approximately 40 in (100 cm) in length.[3]
Within this genus, the number of documented species has varied over the years since its discovery. Prior to his untimely death, Amalitskii described three species, Dvinosaurus primus, Dvinosaurus secundus, and Dvinosaurus tertius.[3] Upon further analysis, however, these three proposed species would be reclassified as solely D. primus as the latter two were found to be age-stages of the same species. Later in the century, Mikhail Shishkin would describe two different species of Dvinosaurus named Dvinosaurus egregius and Dvinosaurus purlensis based on specimens from a locality south of Amalitskii's original site.[5] Finally, in 2004 a new species of Dvinosaurus named D. campbelli was described by Y.M. Gubin based on deposits from the Middle Volga Region, a locality centered around the Volga River, which runs through Western Russia before draining into the Caspian Sea.[6]
- ^ Uliakhin, A. V.; Golubev, V. K. (2024). "Ancient Species of the Genus Dvinosaurus (Temnospondyli, Dvinosauria) from the Permian Sundyr Tetrapod Assemblage of Eastern Europe". Paleontological Journal. 58 (2): 204–225. doi:10.1134/S0031030123600336.
- ^ "PBDB". paleobiodb.org. Retrieved 2020-03-02.
- ^ a b c d Sushkin, P.P. (1936). "Notes on the pre-Jurassic tetrapods from USSR. III. Dvinosaurus amalitzki, a perennibranchiate stegocephalian from the Upper Permian of North Dvina". Akademiya Nauk SSSR, Trudy Paleozoologicheskogo Instituta.
- ^ Bystrow, A.P. (1938). "Dvinosaurus als Neotenische Form der Stegocephalen". Acta Zoologica. 19 (1–2): 209–295. doi:10.1111/j.1463-6395.1938.tb00688.x.
- ^ Shishkin, M.A. (2018). "Comments on the Paper of B.P. Vjuschkov "Locality of Permian Terrestrial Vertebrates in the Vicinities of the Town of Vyazniki"". Paleontological Journal. 52 (2): 175–187. doi:10.1134/S0031030118020120. S2CID 89750532.
- ^ Gubin, Y.M. (2004). "A New Dvinosaur (Amphibia, Temnospondyli) from the Upper Tatarian of the Middle Volga Region". Paleontological Journal. 38: 190–199.