Friday Fossil
Helicoprion is a long-lived genus of extinct, shark-like[2] 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.
Meet the Raptor Dinosaurs of the Mesozoic Era
Name: Utahraptor (Greek for "Utah thief"). Habitat: Plains of North America Historical Period: Early Cretaceous, 130-120 million years ago. Size and Weight: About 23 feet long and 1,000-1,500 pounds. Diet: Meat. Distinguishing Characteristics: Large size; huge claws on feet.