Inostrancevia was a genus of gorgonopsid therapsid found in Sokolki, on the Smaller Northern Dvina River near Arkhangelsk in Russia. The animal lived 251 million years ago during the Late Permian. The species I. alexandri is known from an almost complete skeleton missing some minor rib and vertebrae attachments. As with all other gorgonopsid species, it was a quadruped that had an upright posture of 1-4.3 metres long (as large as a bear), with a bone structure characteristic of strong muscle attachments. The skull of 45 cm in length contained a smaller eye socket and larger temporal opening than other less advanced therapsids, like Biarmosuchus. The teeth were quite large, the upper palate containing 6 large incisors, 2 large canines and 10 smaller back teeth and the mandible contained 6 large incisors and 8 smaller incisors.