What is Coelurosauria?

The most inclusive clade containing Passer domesticus but not Allosaurus fragilis, Carcharodontosaurus saharicus, Sinraptor dongi. When Friedrich von Huene coined Coelurosauria way back in 1914, it was a dumping ground for any and all small carnivorous dinosaurs, and the big ones were housed in Carnosauria. While it's true that the earliest forms from the Middle Jurassic were just mere pups compared to carnosaurs who dominated ecosystems with brutish force until the Late Jurassic, we now know that size alone is no basis for segregation. Some large carnosaurs turned out to be coelurosaurs, some small coelurosaurs turned out to be carnosaurs and, although once thought to be entirely carnivorous, some of them also nibbled on vegetation while others became entirely herbivorous. What a lot of folks (mentioning no creationist names) have trouble accepting is that coelurosaurs are still all around us in the form of modern birds, and likewise at least the smaller, earliest members were feathered.

Carnivorous coelurosaurs (members of Coelurosauria) were built to chase down and snatch prey and, in the case of smaller ones, avoid being snatched themselves. They had long, narrow metatarsals (the bones that connect the ankle to the toes) for speed, canoe-shaped chevrons that gave them an unusually slender tail for counter-balance, and long, thin, three-fingered hands for grasping. Over the process of evolution, coelurosaurs branched out into several groups that developed their own quirks, such as the tyrannosaurids who had just two functional fingers and in some cases were bigger than carnosaurs, the alvarezsaurids who lost yet another digit and ate insects, and therizinosaurids who weighed several tons, were fully vegetarian, and had a pot-belly and a beak. But the coelurosaur brain was always proportionately larger than those of the non-coelurosaurian dinosaurs they lived alongside, which is why (along with a shedload of luck) they are still with us today.

Click here to search Dinochecker for coelurosaurs. Coelurosauria is derived from the Greek "koilos" (hollow), "oura" (tail) "sauros" (lizard), and "-ia" (neuter plural).