Mamenchisauridae


Mamenchisauridae is a family of sauropod dinosaurs known from the Jurassic and Early Cretaceous of Asia and Africa.

Classification

The family Mamenchisauridae was first erected by Chinese paleontologists Yang Zhongjian and Zhao Xijin in 1972, in a paper describing Mamenchisaurus hochuanensis. Other members of Mamenchisauridae include Chuanjiesaurus, Datousaurus, Eomamenchisaurus, Huangshanlong, Hudiesaurus, Qijianglong, Tienshanosaurus, Omeisaurus, Tonganosaurus, Wamweracaudia, Xinjiangtitan, Yuanmousaurus, Zigongosaurus.

Paleogeography

Fossils of Mamenchisaurus and Omeisaurus have been found in the Shaximiao Formation, dating to the Oxfordian-Tithonian interval, around 159-150 Ma. Chuanjiesaurus fossils date between 166.1-163.5 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. The Tendaguru taxon Wamweracaudia extends the geographic distribution of Mamenchisauridae into Africa, while fossil remains from the Itat Formation suggest they also reached Siberia. Additionally, an indeterminate cervical vertebra from the Phu Kradung Formation of Thailand demonstrates survival of Mamenchisauridae into the Cretaceous combined with new radiometric dates for the Suining Formation that has yielded fossils of Mamenchisaurus anyuensis.

Paleobiology

Long-bone histology enables researchers to estimate the age that a specific individual reached. A study by Griebeler et al. examined long bone histological data and concluded that the unnamed mamenchisaurid SGP 2006/9 weighed, reached sexual maturity at 20 years and died at age 31.