Classification: Cellular Life, Archaea, Proteoarchaeota, Eukaryota, Unikota, Opisthokonta, Holozoa, Filozoa, Metazoa, Eumetazoa, Planulozoa, Bilatera, Nephrozoa, Deuterostomia, Chordata, Craniata, Vertebrata, Gnathostomata, Eugnathostomata, Teleostomi, Euteleostomi, Sarcopterygii, Rhipidistia, Tetrapodomorpha, Eotetrapodiforms, Elpistostegalia, Stegocephalia, Tetrapoda, Reptiliomorpha, Anthracosauria, Batrachosauria, Cotylosauria, Amniota, Sauropsida, Eureptilia, Romeriida, Diapsida, Neodiapsida, Sauria, Archosauromorpha, Archelosauria, Archosauriformes, Crurotarsi, Archosauria, Avemetatarsalia, Ornithodira, Dinosauromorpha, Dinosauriformes, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda
Definition: Neotheropods more closely related to Ceolophysis than to Ceratosaurus, Carnotaurus, and Passer
Organisms Within: Gojirasaurus?, Dolichosuchus?, Halticosaurus?, Liliensternus, Lophostropheus, Podokesaurus, Sarcosaurus, Coelophysidae (not examined here)
Time Range: Shown below, numbers on the left in millions of years; organisms in red questionable members of the group. Coelophysoids first appeared fairly early in dinosaurian evolution, further pointing to the evidence that early dinosaurs diversified rapidly. They went extinct not long into the Jurassic period, as other small theropods evolved and outcompeted them for resources.
Coelophysoids were a group of slender, lightly built, fast running theropods that had an extremely flexible jaw, allowing for them to have a wider gape with which to grab potential prey. They were very specialized predators, and in an ecosystem in which most of the other predators were of the bulky and large sort, they were specialized to be the opposite - small, and fast.
Like other early dinosaurs, Coelophysoids were most likely covered in primitive feathers, and were small, bipedal animals with lightweight bones. They grew in size from 1 to 6 meters in length. They may have lived in packs to hunt, and were very successful prior to the Jurassic-Triassic extinction, after which their numbers dwindled. Some members of the group grew crests on their snouts, which were probably used for display.
Fossil Locations: Shown below; red means an organism is a questionable part of the group; colored countries are where fossil locations have been found. Though it is probable that Ceolophysoids may have originated in South America, due to their early appearance in Dinosaurian evolution, it is possible that they evolved elsewhere, given that most Coelophysoids (including Coelophysids, which we’ll look at next week) lived elsewhere.
Biogeography: Names in red indicate questionable members of the group; names in white definite ones. Coelophysoids lived in North America and Europe. All maps from Dr. Christopher Scotese
Post on Coelophysidae to come next week!
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