MEANING: Digging runner
PERIOD: Late Cretaceous
CONTINENT: North America
Oryctodromeus is a basal ornithischian dinosaur that lived in the Late Cretaceous of what is now North America. It was a small, fast running herbivore, and the first non-avian dinosaur discovered with direct evidence of burrowing behavior. Oryctodromeus was about 2 m in body length, and weighed around 30 kg.
Oryctodromeus is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Oryctodromeus is an ornithischian. The name Ornithischia means "bird-hipped," and the group is characterized by a pelvic structure superficially similar to that of birds. Ornithischia consists of mainly herbivorous dinosaurs and reflects this similarity, however, birds themselves to not fall into this group. Ornithischians with well known anatomical adaptations include the ceratopsians and their close relatives, the pachycephalosaurs, the armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, and the ornithopods - bipedal or quadrupedal herbivores including hadrosaurs.