therocephalian

A therocephalian is an extinct member of the clade Therocephalia, a group of mammal-like therapsids within Therapsida. Therocephalians first appear in Middle Permian rocks and become highly diverse during the Late Permian, with fossils found in Africa (notably the Karoo Basin), Asia, and other Gondwanan regions. In many phylogenetic analyses, therocephalians are treated as a sister group to cynodonts, together forming an major division within Therapsida.

Therocephalians varied widely in size and ecology, ranging from small, agile predators to larger carnivores. Their skulls show a mixture of primitive and derived features relative to other therapsids, including differentiated teeth such as canines and post-canine teeth, and robust jaw musculature. Some lineages display trends toward more mammal-like skull features, while others retain more primitive characteristics. Most therocephalians were terrestrial carnivores, though smaller species may have fed on insects or small vertebrates.

In the fossil record, therocephalians are best known from Permian rocks of southern Africa, with additional remains reported from Russia and China. They persisted until the end-Permian mass extinction, after which all lineages disappeared.

Therocephalians are important for understanding early mammal evolution and the broader diversification of therapsids. They illustrate the range of adaptations among mammal-like therapsids prior to the rise of true mammals.