👉 Auchenistius is a genus of extinct mammals that lived during the Late Cretaceous period, approximately 68-79 million years ago. They were characterized by their large, flattened skulls and long limbs, which allowed them to walk on two legs as well as use simple tools for hunting. Auchenistius was part of the larger group of "Mammalia," a vast class of mammals that includes many extinct species.