Such pre-mammal synapsids are often called “proto-mammals” as their anatomy set the stage for what mammals would eventually become. Dimetrodon, in particular, illustrates an early dental shift ...

The species ranged from the 35g proto-mammal Megazostrodon to the 88kg Ophiacodon, and included iconic animals like the sail-backed Dimetrodon and the saber-toothed predator Lycaenops. Using ...