Wikipedia
Apterodon is an extinct genus of Hyaenodontid mammal that lived from the mid Eocene through the Oligocene epoch. With the exception of the type species, A. gaudryi all species of Apterodon are known from Africa. It is closely related to the African Quasiapterodon, and the two genera comprise the Hyaenodontid subfamily Apterodontinae.
Uniquely among hyaenodontids, it was a semi-aquatic, fossorial mammal. It possessed strong forelimbs that were well equipped for digging, compared to those of modern badgers, while the tail, torso and hindlimbs show adaptations similar to those of other aquatic mammals like otters and pinnipeds. The dentition was suited to feed on hard-shelled invertebrate prey, such as crustaceans and shellfish. It probably lived along African coastlines.