Saurischians Temporal range: Late Triassic–Present, 231.4–0 Ma |
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Replica skeleton of an Eoraptor lunensis | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Dinosauria |
Order: |
Saurischia Seeley, 1888 |
Subgroups | |
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Saurischia (/sɔːˈrɪskiə/ saw-RIS-kee-ə, from the Greek sauros (σαυρος) meaning 'lizard' and ischion (ισχιον) meaning "hip joint") is one of the two basic divisions of dinosaurs (the other being Ornithischia). In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure, though today most paleontologists classify Saurischia as an unranked clade rather than an order.
All carnivorous dinosaurs (certain types of theropods) are saurischians, as are all of the birds and one of the two primary lineages of herbivorous dinosaurs, the sauropodomorphs. At the end of the Cretaceous Period, all saurischians except the birds became extinct in the course of the Cretaceous–Paleogene extinction event. Birds, as direct descendants of one group of theropod dinosaurs, are a sub-clade of saurischian dinosaurs in phylogenetic classification.