Final answer:
Tenontosaurus and dryosaurids serve as a transitional evolutionary stage between the smaller hypsilophodontids and the more derived iguanodontids among ornithischian dinosaurs.
Step-by-step explanation:
Tenontosaurus and the dryosaurids are believed to provide an evolutionary link between the hypsilophodontids and iguanodontids. Both the Tenontosaurus and dryosaurids were bipedal herbivorous dinosaurs, with Tenontosaurus often being associated with the earlier part of the Early Cretaceous period and displaying characteristics that were indicative of its transition towards the more derived iguanodontids. The hypsilophodontids, on the other hand, were typically small and fast-moving dinosaurs from the Jurassic and Early Cretaceous periods, which then gave rise to the larger and more advanced iguanodontids. The iguanodontids eventually led to the massive, duck-billed hadrosaurids. These evolutionary connections showcase the diversity and adaptability of ornithischian dinosaurs.
Tenontosaurus and dryosaurids provide an evolutionary link between the hypsilophodontids and iguanodontids.