Eopolycotylus

Eopolycotylus is a type of plesiosaur called a polycotylid, which had a short neck and a long snout.2

Its fossils were found in the Tropic Shale, a rock layer that formed from mud on an ancient seafloor about 91 million years ago.1

The only known specimen is a partial skeleton that includes parts of the skull, jaws, and flippers.1

Eopolycotylus lived during the Turonian stage of the Late Cretaceous, when the Western Interior Seaway covered much of central North America.1

It was a fast swimmer, using its four flippers to chase prey in the warm, shallow sea.2

Scientists think Eopolycotylus gave birth to live young in the water, just like modern whales and dolphins.1