Abdalodon

Abdalodon is an extinct genus of late Permian cynodonts, known by its only species A. diastematicus. Abdalodon, along with the genus Charassognathus, belongs to the clade Charassognathidae. This clade represents the earliest known cynodonts, and is the first known radiation of this group during the Permian.

Abdalodon diastematicus is known from one crushed fossil skull from the Karoo Basin of South Africa. Of all Permian therapsids, cynodonts are among the rarest representatives, with biarmosuchians being the only therapsid group of comparable rarity. The fossil record of Permian cynodonts is characterized by a long ghost lineage. Abdalodon has been important for discerning the early evolution of the group. This genus and its sister taxon Charassognathus are both small therapsids, with the former having a skull around 6 centimetres (2.4 in) in length and the latter being slightly smaller. This suggests that early cynodont evolution occurred at small body sizes, which could explain the rarity of these fossils from the Permian: this is due to an inherent taphonomic bias against the fossilization of small-bodied animals.