| Yuanmousaurus Temporal range:Middle Jurassic | |
|---|---|
 | |
| Size | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Family: | †Mamenchisauridae |
| Genus: | †Yuanmousaurus Lüet al., 2006 |
| Species: | †Y. jiangyiensis |
| Binomial name | |
| †Yuanmousaurus jiangyiensis Lüet al., 2006 | |
Yuanmousaurus ("Yuanmou lizard") was asauropoddinosaur from the MiddleJurassic period ofChina. It is known from incomplete remains, recovered in 2000 from theZhanghe Formation inYuanmou County inYunnan 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 placedYuanmousaurus within thefamilyMamenchisauridae.[1] It may be a dubious genus. The only andtype species wasYuanmousaurus jiangyiensis.[2]
Yuanmousaurus was estimated to be approximately 17 meters (56 ft) in length.[2] 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 basalShunosaurus.[2] 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 thehumerus,ulna,radius,thigh bone,tibia,fibula,astragalus, and a claw from the hind foot.[2] The forelimbs were proportionally longer than in the shortneckedShunosaurus, but shorter than inOmeisaurus: the length ratio between humerus and thigh bone was 0.72 inYuanmousaurus, while it was 0.56 inShunosaurus and 0.80 inOmeisaurus.[2]
The only known specimen, YMV 601, was collected in May 2000 in the villageJiangyi inYuanmou County,Yunnan Province. The fossils are now housed in the Yuanmou Museum. They were described as belonging to a new genus and species, namedYuanmousaurus jiangyiensis, by Lü Junchang and colleagues in 2006. The name references its discovery in Yuanmou County and the village Jiangyi, where the fossils were found.[2]
Yuanmousaurus is deemed to be a basal member of theEusauropoda, standing outside theNeosauropoda, which comprises all more derived sauropods. In itsspecies description,Lü Junchang and colleagues consideredYuanmousaurus a member of theEuhelopodidae that was closely related toPatagosaurus, more basal thanEuhelopus, and more derived thanOmeisaurus.[2] The Euhelopodidae, however, is abandoned by many palaeontologists since the systematic position ofEuhelopus itself is controversial. A newer analysis by Toru Sekiya placesYuanmousaurus within the Mamenchisauridae, together withMamenchisaurus,Tienshanosaurus andChuanjiesaurus.[1] In 2013, a study describing the sauropodNebulasaurus, also from the Zhanghe Formation, evaluated the characters distinguishingYuanmousaurus and considered them invalid, since they were present in other sauropod taxa.[3]
TBA
 | Thissauropodomorph-related article is astub. You can help Wikipedia byadding missing information. |
