Helicoprion, whorl-tooth shark Protoceratops The serial growth forms

The serial growth forms

It is believed that the Messel Pit area was geologically active during the Eocene

and a long

the largest example of Machairodus

Chasmosaur front foot

Helicoprion, whorl-tooth shark Protoceratops The serial growth formsHelicoprion ("Spiral Saw") was a long lived genus of shark like cartilaginous fish that first arose in the oceans of the late Carboniferous 280 million years ago, survived the Permian Triassic Extinction Event, and eventually went extinct during the early Triassic some 225 million years ago. The only fossils known are the teeth, which were arranged in a fantastic "tooth whorl" strongly reminiscent of a circular saw. It was not until the discovery of