 Because the theropod line of dinosaurs that includes "Allosaurus" and "Tyrannosaurus" diverged from the line that led to "Tenontosaurus" very early in the evolution of dinosaurs, this suggests that dinosaurs in general produced medullary tissue and reached reproductive maturity before maximum size.A histological study showed that "T. tilletti" grew quickly early in life and during sub-adult ontogeny, but grew very slowly in the years approaching maturity, unlike other iguanodontians.Throughout the Cloverly Formation, "Tenontosaurus" is by far the most common vertebrate, five times more abundant than the next most common, the ankylosaur "Sauropelta".