Mamenchisaurus
| Mamenchisaurus Temporal range: Late Jurassic to Early Cretaceous (Oxfordian to Aptian), Possible record during the Albian | |
|---|---|
| Mounted skeleton of M. hochuanensis | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Family: | †Mamenchisauridae |
| Genus: | †Mamenchisaurus Young, 1954 |
| Type species | |
| †Mamenchisaurus constructus Young, 1954 | |
| Other species | |
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Mamenchisaurus (/məˌmʌntʃiˈsɔːrəs/ mə-MUN-chee-SOR-əs, or spelling pronunciation /məˌmɛntʃɪˈsɔːrəs/) is an extinct genus of sauropod dinosaurs known for their remarkably long necks which made up nearly half the total body length. Numerous species have been assigned to the genus; however, the validity of these assignments has been questioned. Fossils have been found in the Sichuan Basin and Yunnan Province in China. Several species from the Upper Shaximiao Formation, whose geologic age is uncertain, have been described. However, evidence suggests this formation to be no earlier than the Oxfordian stage of the Late Jurassic. M. sinocanadorum dates to the Oxfordian stage (158.7 to 161.2 mya), and M. anyuensis to the Aptian stage of the Early Cretaceous (around 114.4 mya). Most species were medium-large to large sauropods, measuring roughly 15 to 26 meters (49 to 85 ft) in length—possibly up to 35 meters (115 ft), based on two undescribed vertebrae.