Inostrancevia is an extinct genus of large carnivorous therapsids which lived during the Late Permian in what is now European Russia and Southern Africa. The first-known fossils of this gorgonopsian were discovered in the context of a long series of excavations carried out from 1899 to 1914 in the Northern Dvina, Russia. Among these are two near-complete skeletons embodying the first described specimens of this genus, being also the first gorgonopsian identified in Russia. Several other fossil materials were discovered there, and the various finds led to confusion as to the exact number of valid species, before only two of them were formally recognized, namely I. alexandri and I. latifrons. A third species, I. uralensis, was erected in 1974, but the fossil remains of this taxon are very thin and could come from another genus. More recent research carried out in Southern Africa has discovered specimens identified as belonging to this genus, being classified within the species I. africana. The genus name honors Alexander Inostrantsev, professor of Vladimir P. Amalitsky, the paleontologist who described the taxon. Possessing a skull measuring approximately 40 to 60 cm (16 to 24 in) long depending on the species, all for a body length reaching 3 to 3.5 m (9.8 to 11.5 ft), Inostrancevia is the largest known gorgonopsian, being rivaled in size only by the genus Rubidgea. It has a broad and elongated skull equipped with large oval-shaped temporal fenestrae. It also has very advanced dentition, possessing large canines, the longest of which can reach 15 cm (5.9 in) and which may have been used to shear the skin of prey. Like most other gorgonopsians, Inostrancevia had a particularly large jaw opening angle, which would have allowed it to inflict fatal bites. Gorgonopsians in general would have been relatively fast predators, killing their prey by delivering slashing bites with their saber teeth. The skeleton is robustly constructed, but new studies are necessary for a better anatomical description and understanding about its paleobiological functioning. Gorgonopsians were a group of carnivorous stem mammals with saber teeth that disappeared at the end of the Permian. The first classifications placed Inostrancevia as close to African taxa before 1948, the year in which Friedrich von Huene erected a distinct family, Inostranceviidae. Although this model was mainly followed in the scientific literature of the 20th and early 21st centuries, phylogenetic analysis published since 2018 considers it to belong to a group of derived gorgonopsians of Russian origin, now classified alongside the genera Suchogorgon, Sauroctonus and Pravoslavlevia, this latter and Inostrancevia forming the subfamily Inostranceviinae. Russian and African fossil records show that Inostrancevia lived in river ecosystems containing many tetrapods, where it appears to have been the main predator. These faunas were mainly occupied by dicynodonts and pareiasaurs, which would most likely have constituted its prey. In the Russian territory, Inostrancevia would have been the only large gorgonopsian present, while it would have been briefly contemporary with the rubidgeines in Tanzania. When the rubidgeines disappeared from South African territory, Inostrancevia would have in turn occupied the role of apex predator before disappearing in turn during the Permian-Triassic extinction.
Research history
Russian discoveries During the 1890s, Russian paleontologist Vladimir Amalitsky discovered freshwater sediments dating from the Upper Permian in Northern Dvina, Arkhangelsk Oblast, northern European Russia. The locality, known as PIN 2005, consists of a creek with sandstone and lens-shaped exposures in a bank escarpment, containing many particularly well-preserved fossil skeletons. This type of fauna from this period, previously known only from South Africa and India, is considered as one of the greatest paleontological discoveries of the late 19th and early 20th centuries. After the preliminary reconnaissance of the place, Amalitsky conducts systematic research with his companion Anna P. Amalitsky. The first excavations began in 1899, and several of her findings where sent to Warsaw, Poland, in order to be prepared there. The exhumations of the fossils then lasted until 1914, when the research stopped due to the start of the World War I. When this event begins, Amalitsky tries to save his collection of fossils residing in Warsaw in order to transfer it to the Nizhny Novgorod oblast. However, the arrival of the October Revolution in 1917 and the changing politics within the country indirectly led to his death in December of the same year. Subsequently, his fossil collection was transferred to Leningrad and became an integral part of the geological department of the city's university. During World War II, part of the fossils from the collection were transferred to the Paleontological Institute of the Russian Academy of Sciences in Moscow.
… excerpt ends here. Continue reading the full article.
