abstract:Galesauridae, along with the family Thrinaxodontidae and the large clade Eucynodontia (which includes the mammals) make up the unranked taxon called Epicynodontia. Galesaurids first appeared in the very latest Permian period, just a million years (or perhaps only a thousand years) before the greatest extinction of all time, the Permian-Triassic extinction event.