Mounted Juvenile Tenontosaurus Skeleton
Early Cretaceous, Aptian/Albian Stages
Cloverly Formation, South-Central Montana
Tenontosaurus, has been described as a basal or early iguanodontid, as the skull and teeth would suggest, though, postcranially, it very closely resembles the hypsilophodontids, adding to the uniqueness of this dinosaur that lived in the swamps of the Early Cretaceous. Although it probably ran on two legs, the adult Tenontosaurus was comparatively large and bulky and probably spent most of its time on four legs, grazing.
Juvenile dinosaurs from North America are exceedingly rare. Adding to the rarity of this specimen is the fact that very little of the geologic formation from which it originates is exposed on private land. Almost all of the material known from this area is housed in museums.
Beyond its rarity in the general sense, note the pathology to the right forelimb. There is massive exostosis (extra bone growth) to both bones, and the distal end of one is completely gone. Perhaps this little dinosaur was attacked by a large raptor such as a Deinonychus (a contemporary and very well known predator of this time period and geologic formation), and narrowly escaped. The injury did not kill this diminutive dinosaur, as the massive bone growth after the fact clearly shows. Straight-line measurement from tip of nose to end of tail: 75in; Height, including mount, measures 26 1/2in