Tonganosaurus
Tonganosaurus (named for the town of Tong'an from where it was found) is a genus of mamenchisaurid sauropod dinosaur, similar to Omeisaurus. It is known from one specimen consisting of twenty vertebrae, a front limb and pectoral girdle, and a complete hind limb with partial hip. It lived during the early Jurassic period (Pliensbachian, Yimen Formation), in what is now China.[1] Taking the horizon of the specimen and the age of the Yimen Formation is controversial. Has been assigned three levels to the formation, where Tonganosaurus appears to be of late Early Jurassic age[2] Tonganosaurus is the oldest known member of the family, being near 15 million years older than other members of the group. It was first named by Li Kui, Yang Chun-Yan, Liu Jian and Wang Zheng-Xin in 2010 and the type species is Tonganosaurus hei.[3]
| Tonganosaurus | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Suborder: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Eusauropoda |
| Family: | †Mamenchisauridae |
| Genus: | †Tonganosaurus Li et al., 2010 |
| Species: | †T. hei |
| Binomial name | |
| †Tonganosaurus hei Li et al., 2010 | |
Description
The ratio of the front and rear limbs is 0.80. The tibia was straight and thick, with a length of 0.75 of the femur. Is considered the skeleton of an incomplete adult sauropod dinosaur. Tonganosaurus has been calculated in size, using Omeisaurus as reference the length of the skeleton is estimated to be 11.6 m. The length of the living body maybe was a bit bigger, with around 12 m.[3]
History of discovery
In 2007, the Chengdu University of Technology Museum based on the clues provided by the masses, searched for dinosaurs in Tongan Town, Huili County, Sichuan Province. The fossils come from the middle of the lower part of the Yimen Formation, whose age is estimated on 184.5 m.a. They were inspected and excavated, and a few new Sauropoda dinosaur fossil materials were obtained, including about 20 vertebrae, complete Right shoulder strap and right forelimb, distal left humerus, intact left and right ischia, left femur, and complete right hind limb, and More than 10 scattered spinous nerves, ribs, tibia and claw bones. Where the fossil materials were collected in the same location, and were proportional. Based on that, was suggested these materials represent different parts of the same sauropod. Being the first representative of the family Mamenchisauridae implies a high diversity of sauropods in the late Early Jurassic. The specimen was kept at Chengdu University of Technology Museum, with the number MCDUT 14454.[3]
References
- Yang, C.Y. 2013. Systematic analysis method of Sauropod: a case study of 486 Tonganosaurus hei. Acta Geologica Sinica, 87, 1826-1833. (in Chinese with 487 English abstract)
- Yuan C M. The division and comparison of "Yimen red beds" from Sichuan[J]. Journal of Stratigraphy, 1986, 10(2): 116-120.
- Li, Kui; Yang, Chun-Yan; Liu, Jian and Wang, Zheng-Xin (2010). "A new sauropod dinosaur from the Lower Jurassic of Huili, Sichuan, China" (PDF). Vertebrata PalAsiatica. 48 (3): 185–202.CS1 maint: uses authors parameter (link)
