Mamenchisaurinae

Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods.

Classification

The family Mamenchisauridae was first erected by Chinese paleontologists Yang Zhongjian ("C.C. Young") and Zhao Xijin in 1972, in a paper describing '' Mamenchisaurus hochuanensis''.Young, C.C. and Zhao, X. (1972). "''Mamenchisaurus hochuanensis sp. nov.''". ''Institute of Vertebrate Palaeontology and Palaeoanthropology Monographs'' Series A 8: 1-30.

The most complete cladogram of Mamenchisauridae is presented by Moore ''et al.'', 2020, which includes several named species. Notably, some iterations of their analysis recover '' Euhelopus'' and kin, usually considered somphospondylians, as relatives of mamenchisaurids, mirroring earlier conceptions about the family.

Topology A: Implied-weights analysis, Gonzàlez Riga dataset

Topology B: Time-calibrated Bayesian analysis, Gonzàlez Riga dataset

In addition to several taxa above, a paper by Ren ''et al.'' (2022) also includes '' Rhoetosaurus'', ''Spinophorosaurus'', and '' Yuanmousaurus'' within the family.

Paleobiology

Long-bone histology enables researchers to estimate the age that a specific individual reached. A study by Griebeler et al. (2013) 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.

Paleoecology

Fossils of ''Mamenchisaurus'' and ''Omeisaurus'' have been found in the Shaximiao Formation, dating to the Oxfordian-Tithonian interval, around 159-150 Ma (million years ago). ''Chuanjiesaurus'' fossils date between 166.1 and 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 ( Pliensbachian) Early Jurassic. The Tendaguru Formation taxon '' Wamweracaudia'' from Tanzania extends the geographic distribution of Mamenchisauridae into Africa, while fossil remains from the Itat Formation in Russia 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''.

References

Sources

*

Sauropods
Toarcian first appearances
Early Cretaceous extinctions

Prehistoric dinosaur families

{{Sauropodomorph-stub