theropod

/thear"euh pod'/, n.

any member of the suborder Theropoda, comprising carnivorous dinosaurs that had short forelimbs and walked or ran on their hind legs. Also called bird-footed dinosaur.

[ < NL Theropoda (1881) suborder name; see -THERE, -O-, -PODA]

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Any species of bipedal, carnivorous saurischian in the suborder Theropoda.

The chicken-sized Compsognathus,the smallest known adult dinosaur, probably weighed 2–4 lb (1–2 kg); the tyrannosaurs weighed tons. The theropods also included Allosaurus, Deinonychus, Megalosaurus, Oviraptor, and Velociraptor. Theropod remains recovered have been from the Late Triassic through the Late Cretaceous Epoch (227–65 million years ago) from all continents except Antarctica. Their well-developed hind legs provided support and locomotion; their short forelimbs had mobile hands, probably for grasping and tearing prey. Despite the group's name, which means "beast (i.e., mammal) foot," theropod feet usually resembled those of birds. It is widely believed that all modern birds are descended from one line of small theropods.

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▪ dinosaur suborder

 any member of the dinosaur subgroup, Theropoda, that includes all the flesh-eating dinosaurs. Theropods were the most diverse group of saurischian (“lizard-hipped”) dinosaurs, ranging from the crow-sized Microraptor to the huge Tyrannosaurus rex (tyrannosaur), which weighed six tons or more.

      Unlike the sauropod saurischians, all the theropods were obligate bipeds; that is, their hind legs provided support and locomotion while the short forelimbs and mobile hands were probably adapted for grasping and tearing prey. Despite the group's name, which means “beast (i.e., mammal) foot,” theropod feet usually resembled those of birds. Birds are descended from one lineage of small theropods and therefore are members of Theropoda.

 Three major theropod groups are generally recognized. Ceratosaurs (dinosaur) were the first and ranged in size from the small Coelophysis to Ceratosaurus, which approached Allosaurus in size. Succeeding the early ceratosaurs were the tetanurans, comprising the carnosaurs (carnosaur) (including Allosaurus) and the coelurosaurs (a larger group that includes Tyrannosaurus (tyrannosaur), dromaeosaurs (dromaeosaur), and Ornithomimus, among others). Coelurosaurs and carnosaurs both had many hollow bones and sharp, recurved teeth along the entire length of their jaws.

 Theropod remains have been recovered from all continents except Antarctica and from the Late Triassic (Triassic Period) through the Late Cretaceous periods (Cretaceous Period) (from 227 million to 65 million years ago).

 

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