Exquisitely-Preserved Viper Fish Soft Tissue Preservation Name: Eurypholis boissieri (viper fish) Geological Time: Middle Cretaceous, Cenomanian Stage (95 million years ago) Size (25.4 mm = 1 inch): 87 mm long on a 137 mm by 70 mm matrix Fossil Site: Lebanese Lagerstatt, Haqel, Lebanon
Helicoprion is a long-lived genus of extinct, shark-like eugeneodontid holocephalid fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls." Helicoprion first arose in the oceans of the late Carboniferous 310 million years ago, survived the Permian–Triassic extinction event, and eventually became extinct during the Early Triassic, 250 million years ago. This fossilized jaw shows the spiral dentures.