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. 