10.4" Theropod (Anzu?) Arctometatarsal - Montana

This is a 10.4" long, fossil metatarsal (toe bone) of a large theropod dinosaur. It was collected from the Hell Creek Formation in Powder River County, Montana. The shape of this metatarsal is common in small to large theropods. Organisms that had this middle metatarsal shape are categorized into the "Arctometatarsal" group. The reason for the shape of the bone is still debated, however a plausible hypothesis for the shape is to reduce compressive stress on the foot while running.

The bone is overall in excellent condition and preserved beautifully! There is a repaired crack about 4" away from the distal end of the bone and two at the proximal end of the metatarsal. The proximal-most point of articulation is broken.

It is quite large, but does not appear to be Tyrannosaurid. While we can not definitively provide an ID for it, the giant raptor Anzu wyliei is a likely candidate. In particular because the quarry that this bone came from has produced quite a bit of material from this rare, Hell Creek theropod.

Dubbed by media as the "chicken from hell" this dinosaur grew up to 11 feet in length and sported a large a prominent crest on its head. The name Anzu refers to a feathered demon in ancient Mesopotamian mythology.



The creature's appearance – "big crests on their skulls, a beak, no teeth, and a very bird-like skeleton", and its discovery in the Hell Creek Formation led to it being jokingly nicknamed the "chicken from hell". Matthew Lamanna, who devised the species' name, originally wanted to use a Latin or Greek version of "chicken from hell". However, he found that the nickname did not work so well in those languages.