MEANING: Old runner
PERIOD: Early Jurassic
CONTINENT: Asia
Archaeocursor is a basal ornithischian dinosaur from the Early Jurassic, and the earliest diverging ornithischian yet discovered in Asia. This small-bodied dinosaur had proportionally long legs, indicating it was probably a swift runner. Archaeocursor was most likely herbivorous, and grew to approximately 1 m in length.
Abstract from paper: The Early Jurassic ornithischian dinosaurs in Laurasia are dominated by armored dinosaurs, with other early ornithischian groups being rare. Here, a new taxon, Archaeocursor asiaticus gen. et sp. nov., is reported from the Lower Jurassic of southwestern China. Phylogenetic analysis places Archaeocursor asiaticus as the earliest-diverging ornithischian dinosaur yet discovered in Asia, albeit with weak support. Osteohistological analysis of the femoral cross-section suggests that Archaeocursor asiaticus was a young adult at the time of death, indicating a small body size of approximately 1 meter in body length. This discovery extends the known presence of ornithischian dinosaurs in East Asia to the Pliensbachian or even late Sinemurian stages. Additionally, it points to an earlier dispersal event of Early Jurassic ornithischian dinosaurs from Gondwana to Laurasia, including East Asia, which appears to be independent of, and possibly earlier than, the dispersal of armored dinosaurs.
Archaeocursor is from the Jurassic. The Jurassic is a geologic period that spanned from the end of the Triassic, 201 million y ears ago, to the beginning of the Cretaceous, 145 million years ago. It is the middle period of the Mesozoic Era. The start of the Jurassic was marked by the major Triassic-Jurassic extinction event. The end, however, has no clear boundary with the Cretaceous. By the beginning of the Jurassic, Pangea had begun rifting into two landmasses: Laurasia and Gondwana, and the climate was warm with no ice caps. Life on land was dominated by dinosaurs, and the first birds appeared, evolving from a branch of theropods. The oceans were inhabited by marine reptiles, while pterosaurs were the dominant flying vertebrates.
Archaeocursor 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.