12.5" Fossil Ornithomimid (Struthiomimus?) Femur on Stand - Montana

Fossil Ornithomimid (Struthiomimus?) Femur on Stand - Montana #196696

This is a gorgeous, 12.5" long fossil ornithomimid (Struthiomimus?) femur from the right leg, collected from the Two Medicine Formation of Montana. The diaphysis of the bone was found in several pieces, requiring gap fill restoration and crack repair to piece back together. Much of the restoration begins about 3.5" from the proximal end, with additional gap fill restoration at the distal end of the diaphysis which continues through the metaphysis and through the distal epiphysis. The femoral head is missing (weathered away) at the base of the femoral neck. The majority of the distal epiphysis is in excellent condition, with some minor gap fill restoration (mentioned above).

What makes this bone interesting (and confusing) is its striking resemblance to a Struthiomimus femur. Struthiomimus material has been documented as coming from the Judith River Group, but has yet to be identified in the Two Medicine Formation of Montana, hence the ambiguous provided genus.

This gorgeous specimen is accompanied by the pictured, custom metal display stand.

Measurements:
Length - 12.5" long
Proximal width - 2.6" wide
Distal width - 2" wide
Height on stand - 12.7" tall

Struthiomimus were long-legged, bipedal, ostrich-like dinosaurs with toothless beaks. They reached estimated sizes of approximately 13 feet in length. It is thought that due to their abundance, they must have been herbivores or omnivores.

Struthiomimus sedens skeleton in the Oxford University Museum of Natural History

The Two Medicine Formation is a geographical formation in Central Montana and Southern Alberta, Canada. The formation is predominantly sandstone laid down by rivers and deltas during the Campanian Age of the Cretaceous, about 80-75 million years ago. Approximately two thousand feet thick on the western edge, it lies on top of the Virgelle Sandstone formation and under the Bearpaw Shale. It is located between the Front Range of the Rocky Mountains and the Sweetgrass Arch, a tectonic fold feature 40-90 miles east of the Front Range.

The Two Medicine is the same age as the Judith River Formation found further east. It was laid down further inland from the Western Interior Seaway, while the Judith River Formation was deposited along the coast. The Two Medicine contains much of the same dinosaur fauna, but fewer reptiles, amphibians, and aquatic fossils.

A view of the Two Medicine Formation quarry operated by Northwest Montana Fossils, where much of our Two Medicine dinosaur material has been found.

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