Mamenchisauridae

Mamenchisauridae Temporal range: 184.5–114  Ma PreꞒ Ꞓ O S D C P T J K Pg N Possible Albian record
Mamenchisaurus
Skeleton of Mamenchisaurus hochuanensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	†Sauropodomorpha
Clade:	†Sauropoda
Clade:	†Eusauropoda
Family:	†Mamenchisauridae Young and Zhao, 1972
Genera
†Analong †Anhuilong †Bellusaurus? †Chuanjiesaurus †Daanosaurus? †Datousaurus? †Eomamenchisaurus †Huangshanlong †Hudiesaurus †Jingiella[1] †Klamelisaurus †Mamenchisaurus †Omeisaurus †Qijianglong †Rhoetosaurus? †Rhomaleopakhus †Spinophorosaurus? †Tienshanosaurus †Tonganosaurus †Wamweracaudia †Xinjiangtitan †Yuanmousaurus †Zigongosaurus
Synonyms
Omeisauridae Wilson, 2002

Mamenchisauridae is a family of

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.^[3]

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.^[4]

Topology A: Implied-weights analysis, Gonzàlez Riga dataset^[4]

Topology B: Time-calibrated Bayesian analysis, Gonzàlez Riga dataset^[4]

In addition to several taxa above, a paper by Ren et al. (2022) also includes Rhoetosaurus, Spinophorosaurus, and Yuanmousaurus within the family.^[5]

A 2023 study also includes Hudiesaurus, Xinjiangtitan, Rhomaleopakhus, and the juvenile Bellusaurus and Daanosaurus within the family.^[6]

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 25,075 kilograms (27.6 short tons), reached sexual maturity at 20 years and died at age 31.^[7]

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.^[8] Fossils of Tonganosaurus date to even earlier, from the (Pliensbachian) Early Jurassic.^[9] The Tendaguru Formation taxon Wamweracaudia from Tanzania extends the geographic distribution of Mamenchisauridae into Africa,^[10] while fossil remains from the Itat Formation in Russia suggest they also reached Siberia.^[11] 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.^[12][13]

References