Yuanmousaurus
Yuanmousaurus ("Yuanmou lizard") was a sauropod dinosaur from the Middle Jurassic period of China. It is known from incomplete remains, recovered in 2000 from the Zhanghe Formation in Yuanmou County in Yunnan Province. "Yuanmousaurus" was a relatively large sauropod and may have reached about 17 meters (56 ft) in length. It was a basal member of the Sauropoda, but its exact systematic position is unclear. A recent study placed "Yuanmousaurus" within the family Mamenchisauridae. The only and type species was "Yuanmousaurus jiangyiensis". Description. "Yuanmousaurus" was estimated to be approximately 17 meters (56 ft) in length. The skull is missing , while the neck is known only from a fragment of a posterior cervical vertebra. This fragment indicates elongated neck vertebrae, similar to those of mamenchisaurid sauropods, but unlike the much shorter neck vertebrae of the more basal "Shunosaurus". From the trunk and tail, nine dorsal, three sacral and seven caudal vertebrae were found. While the shoulder and pelvic girdles are missing with the exception of one ilium, the limbs are better known, including the humerus, ulna, radius, thigh bone, tibia, fibula, astragalus, and a claw from the hind foot. The forelimbs were proportionally longer than in the shortnecked "Shunosaurus", but  shorter than in "Omeisaurus": the length ratio between humerus and thigh bone was 0.72 in "Yuanmousaurus", while it was 0.56 in "Shunosaurus" and 0.80 in "Omeisaurus". Classification. "Yuanmousaurus" is deemed to be a basal member of the Eusauropoda, standing outside the Neosauropoda, which comprises all more derived sauropods. In its species description, Lü Junchang and colleagues considered "Yuanmousaurus" a member of the Euhelopodidae that was closely related to "Patagosaurus", more basal than "Euhelopus", and more derived than "Omeisaurus". The Euhelopodidae, however, is abandoned by many palaeontologists since the systematic position of "Euhelopus" itself is controversial. A newer analysis by Toru  Sekiya places "Yuanmousaurus" within the Mamenchisauridae, together with "Mamenchisaurus", "Tienshanosaurus" and "Chuanjiesaurus". Discovery. The only skeleton (YMV 601) was recovered in May 2000 in the village Jiangyi in Yuanmou County, Yunnan Province. The excavation was led by palaeontologists of the Yunnan Provincial Institute of Cultural Relics and Archaeology, the Yuanmou Museum and the Chuxiong Museum. Today, the fossils are part of the Yuanmou Museum collection. They were described as "Yuanmousaurus jiangyiensis" by Lü Junchang and colleagues in 2006. The name adverts to Yuanmou County and the village Jiangyi, where the fossils were found.