stegosaur

Stegosaur, commonly used for members of the clade Stegosauria, refers to a group of herbivorous, armored dinosaurs that lived during the Middle to Late Jurassic period, roughly 167 to 150 million years ago. Stegosauria is a subdivision of Thyreophora within Ornithischia. The best known genus is Stegosaurus, from North America, but other stegosaurs include Huayangosaurus (China), Kentrosaurus (Africa), and Dacentrurus (Europe).

Stegosaurs are characterized by a row of large, flat, sometimes rounded plates along the back and a set of pointed tail spikes called thagomizers. They had small heads, beaked mouths, and leaf-shaped teeth suited to herbivory. Most species had forelimbs shorter than hindlimbs, giving a somewhat upright posture; they were predominantly quadrupedal as adults, though juveniles may have spent more time bipedal.

The plates' function is debated; hypotheses include thermoregulation, display to peers or predators, or species recognition. The tail spikes provided a defensive weapon. Stegosaurs were low-browsing feeders, feeding on low-growing vegetation and ferns. Their fossils are found in what were once coastal and inland habitats of Laurasia and Gondwana during the Jurassic; they disappeared by the end of the Jurassic.