Gorgonopsidae

Gorgonopsians were theriodont therapsid synapsids belonging to the Suborder Gorgonopsia. "Gorgonopsia" means "Gorgon face" or "Gorgon arch" after the Gorgons of Greek mythology. Gorgonopsians evolved from a reptile-like therapsid in the Middle Permian. The early forms were small, being no larger than a dog. Dinocephalians dominated the Middle Permian. After dinocepahlians became extinct, gorgonopsians became the dominant predators of the Late Permian. Some approached the size of a rhinoceros, tiger or large bear [3][4], up to 5m long from head to tail. Gorgonopsians became extinct at the end of the Permian.

Their mammalian specializations include differentiated (heterodont) tooth shape, a fully developed temporal fenestra, pillar-like rear legs, a vaulted palate, which may have aided breathing while holding prey, and incipiently developed ear bones [1]. Gorgonopsians probably lacked fur, but may have evolved scent glands in their skin (6). They were the first animals to have huge jaws containing the lethal canines called sabre teeth, as a response to a carnivorous life style (6); these fangs were up to 12cm long. Unlike the later mammalian sabre-toothed predators, the teeth of gorgonopsians showed less differentiation and specializations and their jaws were relatively long and thin. Gorgonopsiand didn't use molars or carnassials to chew; they didn't chew at all. They used their teeth and jaws to rip away large chunks of meat and swallow them whole, rather like modern crocodilians do. They had definite canines, incisors and molar-like teeth, especially in their upper jaws. They were fast and powerful and ate a variety of prey, including Labyrinthodonts (such as Rhinesuchus), Diictodons and Scutosaurs. One snap of their enormous jaws could crush a Diictodon, if they could get a grip. Gorgonopsians include three subfamilies: Gorgonopsinae, Rubidgeinae and Inostranceviinae, as well as several genera not placed in any of these groups. Gebauer (5) did not consider Gorgonopsia and Gorgonopsidae to be equivalent. She only placed species with autapomorphies, or characteristics unique to those species, in the Gorgonopsidae. She placed Aloposaurus, Cyonosaurus and Aelurosaurus outside theGorgonopsidae as "stem-gorgonopsids" oubecause they did not have autapomorphies. Gebauer (5) listed the following genera:

Gorgonopsia: Cyonosaurus, Aelurosaurus

Gorgonopsidae: Scylacognathus, Eoarctops, Gorgonops, Njalila, Lycaenops, Arctognathus, Inostrancevia

Rubidgeinae: Aelurognathus, Rubidgea, Sycosaurus, Clelandina,