1.9" Partial, Pachycephalosaurus Toe Bone (Metatarsal) - North Dakota

This is a partial, 1.9" long metatarsal (toe bone) of the dinosaur Pachycephalosaurus ("thick headed lizard"). It was collected from the Hell Creek Formation in Montana. There is a repaired crack running through the entire bone.

Pachycephalosaurus was a bipedal dinosaur that lived during the Late Cretaceous period and probably was about 15 feet in length.

Pachycephalosaurus had a distinctive, large, bony, dome on top of it's skull up to 10 inches thick to cushion it's brain from impacts.

Some paleontologists believe this thick skull may have been used for head-butting, much like rams while others contend it may have been a sexual display.

It was one of the last non-avian dinosaurs before the K-T extinction event, 65 million years ago.

There is only one known species of Pachycephalosaurus, Pachycephalosaurus wyomingensis. It's remains have been found in Montana, South Dakota and Wyoming.

It was either a herbivore or an omnivore with small leaf shaped teeth which would have been very effective at shredding plants.