a nearly complete skeleton, several skulls, and additional postcrania from several individuals. The best of these skeletons, a nearly complete and semi articulated postcranial skeleton (ZDM T5701), was selected as the holotype and described by He et al in 1984. A nearly complete skull and partial postcranial skeleton (ZDM T5702) was selected as the paratype, and was is one of the few known Omeisaurus specimens with a well preserved skull. The several specimens were described in much detail later in 1988, with a skeleton mounted at the Zigong Dinosaur Museum sometime later. Interestingly, O. tianfuensis was discovered to have a tail club on the end of its caudal vertebrae based on a specimen from Dashanpu. A second new species was named in 1988, O. luoquanensis, in the osteology of O. tianfuensis off of a partial postcranial skeleton. Recent discoveries Several Omeisaurus species have been named since the 1980s, with the most complete of them coming in 2001 with Omeisaurus maoianus from the Shaximiao Formation in Jingyan. O. maoianus was collected by Jin Xingshen and Zhang Guojin during the 1990s and the remains consisted of a skull, partial vertebral column, and several additional postcranial elements (ZNM N8510). O. maoianus was mounted at the Zhejiang Natural History Museum with its holotype skull on display. O. maoianus''' generic assessment has been questioned, with several phylogenetic analyses finding it more closely related to Mamenchisaurus and Xinjiangtitan. 10 years later in 2011, Omeisaurus jiaoi was named based on a well preserved and partially articulated postcranial skeleton, also from Zigong and is deposited at the Zigong Dinosaur Museum (ZDM 5050). The most recently named Omeisaurus species, O. puxiani, was discovered in Yunyang and is one of the best preserved Omeisaurus species, with fossils from most of the vertebral column and girdles recovered. The specimen is deposited under CLGRP V00005 at the Chongqing Laboratory of Geoheritage Protection and Research. Classification It was once classified as a member of the family Cetiosauridae, which had long been a wastebasket taxon. The species O. fuxiensis is sometimes confused with Zigongosaurus, but the two are based on different material despite having the same species name.Omeisaurus was formerly assigned to Euhelopodidae. However, it and other Jurassic sauropods from Asia formerly assigned to Euhelopodidae are now placed in the separate family Mamenchisauridae, which is more basal in Sauropoda. In 2021, John D'Angelo determined that all Omeisaurus species, besides O. maoianus, were valid and