Sarkastodon

Sarkastodon ("flesh-tearing tooth") is an extinct genus of placental mammals from the extinct subfamily Oxyaeninae within the extinct family Oxyaenidae. The genus lived in Asia (in today's China and Mongolia) during the middle Eocene and was the last known oxyaenid. The first fossil of Sarkastodon, part of a lower jaw, was discovered in 1928 in one of the Central Asiatic Expeditions. The second, consisting of the front of the skull and two partial lower jaws, was discovered by a surgeon, Dr. A. Z. Garber, in the final expedition, two years later. Recognised as a "relatively colossal" oxyaenid, it was named in 1938 by Walter W. Garber. Two species have been described: S. mongoliensis from the Irdin Manha Formation of Mongolia, and S. henanensis, named in 1986 based on remains from the Hetaoyuan Formation of China.

Sarkastodon has an estimated length of 3 m (9.8 ft). In 2009, it was estimated to have had a body mass of about 800 kg (1,800 lb), although given the methodology used, the accuracy of this estimate was called into question by its own proponent. Though incomplete, the holotype skull of S. mongoliensis was 35 cm (14 in) in total length, with a width across the zygomatic arches of 38 cm (15 in). The skull overall would have been about half as big again as that of Patriofelis, which had been considered the largest oxyaenid until Sarkastodon's naming. The two genera had fairly similar skulls, and were differentiated mainly based on attributes of their teeth. The enamel bands in the teeth of Sarkastodon, known as Hunter-Schreger bands, formed a zig-zag shape, which may be an adaptation for bone-processing.