Is there a transitional species between a amphibian tetrapod and a reptillian amniote?
Saurian synapsids, right? I know there were two kind of synapsids, one branch of which was the mammalian synapsids and the other the ancestors of birds and reptiles.
Edit: I don’t know much about them myself, sorry, but at least I can give you a starting point
here i found a whole list of them