Mamenchisauridae is a family ofsauropoddinosaurs belonging to theEusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Mamenchisaurids are characterized by their proportionately extremely long necks. Some members of the group reached gigantic sizes, amongst the largest of all sauropods.[1]
A comprehensive analysis of Mamenchisauridae was presented by Moore et al., 2020, including several named species. Notably, some iterations of their analyses recoveredEuhelopus and kin, usually consideredsomphospondylians, as relatives of mamenchisaurids, mirroring earlier conceptions about the family.[3]
The 2023 redescription ofMamenchisaurus sinocanadorum incorporated updated versions of a matrix from Moore et al. (2020). These results are displayed in thecladogram below:[4]
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.[5]
Fossils ofMamenchisaurus andOmeisaurus have been found in theShaximiao 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 ofEomamenchisaurus were found in theZhanghe Formation, believed to be around 175.6-161.2 million years old.[6] Fossils ofTonganosaurus date to even earlier, from the (Pliensbachian) Early Jurassic.[7] TheTendaguru Formation taxonWamweracaudia from Tanzania extends the geographic distribution of Mamenchisauridae into Africa,[8] while fossil remains from theItat Formation in Russia suggest they also reached Siberia.[9] Additionally, an indeterminate cervical vertebra from thePhu Kradung Formation of Thailand demonstrates survival of Mamenchisauridae into the Cretaceous combined with new radiometric dates for the Suining Formation that has yielded fossils ofMamenchisaurus anyuensis.[10][11]
^Young, C.C. and Zhao, X. (1972). "Mamenchisaurus hochuanensis sp. nov.".Institute of Vertebrate Palaeontology and Palaeoanthropology Monographs Series A 8: 1-30.
^Moore, A.J.; Upchurch, P.; Barrett, P.M.; Clark, J.M.; Xing, X. (2020). "Osteology ofKlamelisaurus gobiensis (Dinosauria, Eusauropoda) and the evolutionary history of Middle–Late Jurassic Chinese sauropods".Journal of Systematic Palaeontology.18 (16):1299–1393.doi:10.1080/14772019.2020.1759706.S2CID219749618.
^Griebeler EM, Klein N, Sander PM (2013) Aging, Maturation and Growth of Sauropodomorph Dinosaurs as Deduced from Growth Curves Using Long Bone Histological Data: An Assessment of Methodological Constraints and Solutions. PLoS ONE 8(6): e67012. doi:10.1371/journal.pone.0067012
^Junchang L, Tianguang L, Shimin Z, Qiang J, Shaoxue L (February 2008). "A new mamenchisaurid dinosaur from the Middle Jurassic of Yuanmou, Yunnan Province, China".Acta Geologica Sinica - English Edition.82 (1):17–26.doi:10.1111/j.1755-6724.2008.tb00320.x.S2CID128454888.
^Li K, Yang CY, Liu J, Wang ZX (2010). "A new auropod dinosaur from the Lower Jyrassic of Huili, Sichuan, China".Vertebrata PalAsiatica.3.
^Mannion PD, Upchurch P, Schwarz D, Wings O (February 2019). "Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution".Zoological Journal of the Linnean Society.185 (m 3):784–909.doi:10.1093/zoolinnean/zly068.hdl:10044/1/64080.
^Averianov A, Krasnolutskii S, Ivantsov S, Skutschas P, Schellhorn R, Schultz J, Martin T (2019). "Sauropod remains from the Middle Jurassic Itat Formation of West Siberia, Russia".PalZ.93 (4):691–701.doi:10.1007/s12542-018-00445-8.S2CID135205021.
^Wang J, Norell MA, Pei R, Ye Y, Chang SC (December 2019). "Surprisingly young age for the mamenchisaurid sauropods in South China".Cretaceous Research.104: 104176.doi:10.1016/j.cretres.2019.07.006.S2CID199099072.
