Overview
Theropoda is one of the three major clades of dinosaurs, alongside Ornithischia and Sauropodomorpha. Theropods, both extant and extinct, are characterized by hollow bones and three toes and claws on each limb. They are generally classed as saurischian dinosaurs, placing them closer to sauropodomorphs than to ornithischians. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Many members of the subgroup Coelurosauria were covered with feathers, and it is possible that they were also present in other theropods. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, to about 11,000 living species, making theropods the only group of dinosaurs that remain.