Mamenchisauridae is an extinct family of sauropod dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s. The family was first named by Chinese paleontologists C.C. Young and H.C. Chao in 1972, in a paper describing Mamenchisaurus

Mamenchisaurus

Mamenchisaurus was a plant-eating four-legged dinosaur, known for its remarkably long neck which made up half its total length. It is known from numerous species which ranged in time from 160 to 145 million years ago, from the Oxfordian to Tithonian ages of the late Jurassic Period of...

. Other mamenchisaurids may include Bellusaurus

Bellusaurus

Bellusaurus was a small short-necked sauropod dinosaur from the Middle Jurassic which measured about long...

, Chuanjiesaurus

Chuanjiesaurus

Chuanjiesaurus was a genus of dinosaur from the Middle Jurassic Period. It lived in what is now present-day China. It is classified as a sauropod. The type species, Chuanjiesaurus ananensis, was first described by Fang, Pang, Lü, Zhang, Pan, Wang, Li and Cheng in 2000...

, Eomamenchisaurus

Eomamenchisaurus

Eomamenchisaurus is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lu et al. in 2008....

, Hudiesaurus

Hudiesaurus

Hudiesaurus is a genus of dinosaur from China. A sauropod, it may have been related to Mamenchisaurus. Its fossil remains were found in the Kalazha Formation, which dates to the late Jurassic Period. The type species, Hudiesaurus sinojapanorum, is known from only two incomplete specimens...

, Klamelisaurus

Klamelisaurus

Klamelisaurus is the name given to a genus of dinosaur from the Middle Jurassic. It was a sauropod similar to Bellusaurus, of which it may actually be an adult specimen. It was found in the Gobi desert of Asia.The type species, K...

, Omeisaurus

Omeisaurus

Omeisaurus is a genus of sauropod dinosaur from the Middle Jurassic Period of what is now China. Its name comes from Mount Emei, where it was discovered in the lower Shaximiao Formation of Sichuan Province.Like other sauropods, Omeisaurus was herbivorous and large...

, and Tonganosaurus

Tonganosaurus

Tonganosaurus is a genus of mamenchisaurid sauropod dinosaur, similar to Omeisaurus. It is known from one specimen consisting of twenty vertebrae, a front limb and pectoral girdle, and a complete hind limb with partial hip. It lived during the early Jurassic period in what is now China...

. Fossils of Mamenchisaurus and Omeisaurus have been found in the Shangshaximiao Formation, dating to the Oxfordian stage

Oxfordian stage

The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma...

, around 161.2-155.7 Ma (million years ago). Chuanjiesaurus fossils date between 175.6-161.2 Ma, while those of Eomamenchisaurus were found in the Zhanghe Formation, believed to be around 175.6-161.2 million years old. Fossils of Tonganosaurus date to even earlier, from the Early Jurassic.