Paleothyris

Paleothyris was a small, agile, anapsid reptile which lived in the Pennsylvanian epoch in Nova Scotia (about 312 to 304 million years ago). 
"Paleothyris" had sharp teeth and large eyes: it was a nocturnal hunter. It was about a foot long. It probably fed on insects and other smaller animals found on the floor of its forest home. 
"Paleothyris" was an early sauropsid, yet it still had some features that were more labyrinthodont-like than reptile-like. Its skull lacked fenestrae, holes found in the skulls of most reptiles and mammals.