Fossil skull of the extinct cynodont therapsid Cynognathus crateronotus. Cynognathus was a powerful predator that was close to being a mammal, but not quite. It has been found in several parts of ...

Exhibit specimen of Edaphosaurus, a pelycosaur synapsid, from the collections at the Museum of Comparative Zoology. Pelycosaurs are the most ancient forerunners of mammals. This study shows that ...

Color-coded diagram of a small bone bed containing at least twelve individuals of the Permian synapsid Suminia. From Frobisch and Reisz (2009) *[In other words, all living mammals shared a common ...

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American With hues inspired by calcite and a plastic ...