Dinosauromorph

dinosauromorph, any of a group of archosaurian reptiles that includes dinosaurs and all other reptiles bearing a closer evolutionary relationship to dinosaurs than to pterosaurs. Dinosaurs include birds and other theropods, sauropodomorphs, and ornithischians—familiar animals that embody the concept of “Dinosauria” erected by British anatomist and paleontologist Richard Owen in 1842, long before the present diversity and relationships of dinosaurs were known. In contrast, the clade Dinosauromorpha includes all these dinosaurs plus some other dinosaur-like reptiles that possess some, but not all, of the features of dinosaurs.

In the 1980s it was discovered that dinosaurs and the Pterosauria, a group containing flying reptiles called pterosaurs, shared some important features of the skull, vertebral column, and limbs that indicated a close common ancestry. In short, these two major groups of archosaurs from the Mesozoic Era are often regarded as each other’s closest relatives. It was discovered, however, that some nondinosaurian reptiles were more closely related to dinosaurs than to pterosaurs. Such reptiles are included with the dinosaurs in the Dinosauromorpha. Likewise, those archosaurs that include pterosaurs and other animals closer to them than to dinosaurs are considered to be part of the Pterosauromorpha.