(Gk. pelyx, “bowl” + sauros, “lizard”)


Dimetrodon (source)

Unlike true lizards, the pelycosaurs had no scales.  Parts of their skin were naked, but they had dermal scutes on their bellies.  Dermal scutes are also found on the tails of beavers, rats, and opossums, and they make up the armor of the armadillo.

The pelycosaurs were the forefathers and foremothers of the therapsids, of which we mammals are the last survivors, so far.

A great deal more about everything here.