the skeletal remains of "protoclepsydrops" suggest it may have been a synapsid. if so, it is the oldest synapsid known, though its status is unconfirmed because its remains were fragmentary. "protoclepsydrops" lived slightly earlier than "archaeothyris", which was definitely a synapsid. like "archaeothyris", "protoclepsydrops" had a body shape which resembled modern lizards.