Fish Pharedous sp.

A huge system of lakes stretched out where 40 million later would be the US state of Wyoming. The Green River Formation holds fossilized traces of that ancient life. And above all, these are perfectly preserved fish skeletons. Overgrown with grass and mud, coastal backwaters were home to fish of the genus Phareodus, relatives of modern arapaima. Unlike its large relative, Phareodus had a dense short body and small size. The fins shifted back and strong back muscles made this fish maneuverable, which helped to hide from numerous predators of that era.