The oldest known fossil synapsid is Protoclepsydrops from about 320 million years ago , while the oldest known sauropsid is probably Paleothyris , in the order Captorhinida , from the Middle Pennsylvanian epoch -LRB- ca . 306-312 million years ago -RRB- .
The oldest known fossil synapsid is Protoclepsydrops from about 320 million years ago , while the oldest known sauropsid is probably Paleothyris , in the order Captorhinida , from the Middle Pennsylvanian epoch -LRB- about 306-312 million years ago -RRB- .
The oldest known fossil synapsid is Protoclepsydrops from about 320 million years ago , while the oldest known sauropsid is probably Paleothyris , in the order Captorhinida , from the Middle Pennsylvanian epoch -LRB- about 306-312 million years ago -RRB- .
Use simpler wording: The oldest known fossil synapsid is Protoclepsydrops from about 320 million years ago , while the oldest known sauropsid is probably Paleothyris , in the order Captorhinida , from the Middle Pennsylvanian epoch -LRB- ca . 306-312 million years ago -RRB- . Output: