Abdalodon

Abdalodon is an extinct genus of late Permian cynodonts, known by its only species A. diastematicus. Abdalodon together with the genus Charassognathus, form the clade Charassognathidae. This clade represents the earliest known cynodonts, and is the first known radiation of Permian cynodonts.

Abdalodon diastematicus is known from one crushed fossil skull from the Karoo Basin of South Africa. Of all Permian Therapsids, cynodonts are among the most rare (Biarmosuchians being the only therapsids being 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 cynodonts. Abdalodon, and its sister taxa Charassognathus are both small bodied animals, Abdalodon having a skull around six centimeters in length and the Charassognathus skull being slightly smaller. This suggests that early cynodont evolution occurred at small body size, which could explain the rarity of Permian cynodont fossils, because there is an inherent taphonomic bias against the fossilization of small bodied animals.