Synapsid

Synapsid is the evolutionary of the mammal species. They have both mammal and reptile characteristics such as scent glens, laying eggs and scaly skin. They appeared during the Carboniferous Period and all died out at the end of the Triassic period. The closest living resembles to the Synapsid is the Monatreams a mammal group that appeared after the Synapsid died out during the end of the Triassic. They are warm blooded but instead of giving live birth they laid eggs.