Minda Berbeco's picture

Answer Monday!

Last week on Fossil Friday, I gave you an entire body (minus the head!) and a simple request: identify this fossil, where it was found, and what the heck a "synapsid" is. There were many valiant attempts, but the best came from Clayton Pilbro:

"Sphenacodon possibly ferox, Permian, known from New Mexico, Arizona, and Utah, North America. Synapsids are a group of animals that are related to mammals and other currently living amniotes. They posses a derived temporal fenestra with a single arch (making a bar of bone behind the eye orbit). Synapsids were the largest terrestrial vertebrates of the Permian."

Sure enough, this Sephanocodon ferox fossil was found right in New Mexico—stellar job Clayton!

From the UC Museum of Paleontology on synapsids:

"The mammals of today are but one branch of the Synapsida, a great vertebrate group with a 300 million year history. Pre-mammalian synapsids—including the famous "finback" Dimetrodon, shown at the top left—dominated the land vertebrate fauna of the Permian and early Triassic before losing ground to the diversifying dinosaurs and other archosaurs. These pre-mammalian groups of synapsids have at times been called "mammal-like reptiles". This term is now discouraged because although many had characteristics in common with mammals, none of them were actually reptiles."

Thanks for playing Fossil Friday. Stay tuned for more exciting fossils later this week!