.90" Hadrosaur (Lambeosaurus?) Tooth - Judith River Formation

Lambeosaurus (meaning Lambe's lizard) was a crested hadrosaur that lived in the late Cretaceous period of what is now North America, 76-75 million years ago. This herbivorous dinosaur would have grown to a length of 25 feet and about 3-4 tons at adult size. Its hands were hoof-like in shape, and based on skin impressions would have been surrounded in flesh like a sort of "mitten". Perhaps most notably, Lambeosaurus had a large, hollow, bony crest at the back of its skull in a tall, flat, rounded shape. The purpose of this crest isn't entirely certain, but likely theories include sexual and social displays. The crests show great disparity between species and possibly between the sexes: some specimens display much smaller crests than others.

The Judith River Formation is one of the world's most prolific sources of Late Cretaceous vertebrate fossils. At least sixteen Orders containing more than forty Genera are known from the formation. These include fish, amphibians, mammals, and insects in addition to reptiles and avian (birds) and non-avian dinosaurs. Among the more interesting specimens is Leonardo, a mummified and fossilized Brachylophosaurus. This is a hadrosaur, a duck-billed dinosaur found with amazing soft-tissue preservation: skin impressions can be found on 90 percent of its body! The pattern in the skin on its feet is even preserved. In addition to Leonardo, the Judith River Formation contains the remains of the theropod Hesperornis, the only known freshwater Hespernorthid, a penguin-like bird.