1.5" Unidentified Dinosaur Caudal Vertebrae - Hell Creek Formation

This is a nicely preserved, caudal (tail) vertebrae most likely from Thescelosaurus. Isolated vertebrae from Thescelosaurus and Pachycephalosaurus are be basically indistinguishable without the full process present. Based on the abundance of material in the Hell Creek Formation odds heavily favor Thescelosaurus.

Thescelosaurus was a small ornithopod dinosaur that appeared at the very end of the Late Cretaceous period in North America. The preservation and completeness of many of its specimens indicate that it may have preferred to live near streams. This bipedal ornithopod is known from several partial skeletons and skulls that indicate it grew to between 2.5 and 4.0 meters (8.2 to 13.1 ft) in length on average. It had sturdy hind limbs, small wide hands, and a head with an elongate pointed snout. The form of the teeth and jaws suggest a primarily herbivorous animal.

Pachycephalosaurus was a bipedal dinosaur that lived during the Late Cretaceous period and probably was about 15 feet in length. It had a distinctive, large, bony, dome on top of it's skull up to 10 inches thick to cushion it's brain from impacts.