Theropoda

Theropoda is one of the three major clades of dinosaurs, alongside Ornithischia and Sauropodomorpha, and is generally grouped among the saurischians as a nearer relative of the sauropodomorphs. Theropods were ancestrally carnivorous and included the majority of large terrestrial predators from the Early Jurassic until the end of the Cretaceous, among them the largest meat-eating land animals ever to exist, such as Tyrannosaurus and Giganotosaurus. First appearing in the Late Triassic, the group spans an enormous range of body sizes and lifestyles, with several lineages independently shifting to herbivory or omnivory. Its major subgroups include the early coelophysoids and the often horned ceratosaurs, together with the sprawling tetanuran radiation, which encompasses the semiaquatic spinosaurids, the allosauroids, and the feathered coelurosaurs, the last including tyrannosaurids, ornithomimosaurs, dromaeosaurids, and therizinosaurs. From small, specialized coelurosaurs, birds arose during the Jurassic and endure today as roughly 11,000 living species, making theropods the only dinosaur lineage still present on Earth.