Tienshanosaurus
- Xinjiang, China ( Shishugou Formation)
- Tienshanosaurus chitaiensis Young, 1937
Tienshanosaurus is a little known genus of sauropod dinosaur from the Upper Jurassic of China. It was already in 1937 by CC Young ( Yang Zhongjian ) first described scientifically, so it was - after Euhelopus - to the second described sauropods, which was discovered in China. The first description was based on a skull -less skeleton, which originated in the autonomous Chinese region of Xinjiang from the Shishugou lineup and could be dated to the Oxfordian. Later, the genus further discoveries were attributed. Today, all finds are destroyed except for a 1930 discovered scapula.
It is unclear to which group within the sauropods this genus is to count, although the most recent study suggests a classification within the Mamenchisauridae. Some researchers consider the genus as currently noun dubium ( genus of doubtful validity ), as no features are known that uniquely distinguish the genus from other genera. The only species of the genus is Tienshanosaurus chitaiensis.
Features
As with all sauropods, there was a four-legged herbivore with a long neck and tail. Tienshanosaurus was a relatively small sauropod - Youg (1937 ) estimated the first specimen found at about 10 meters overall length. Compared with other sauropods, the vertebrae were relatively short and had to thin cervical ribs which jutted back over the posterior margin of the vertebral body. The posterior dorsal vertebrae were characterized by weak lateral cavities ( Pleurocoele ), while these were absent in the caudal vertebrae. The posterior dorsal vertebrae and the lumbar vertebrae were amphicoel (on the front and back concave). The scapula had a long shaft and a broad proximal (front ) end, the coracoid ( coracoid ) was small. The humerus was relatively slim while the ilium was short and high.
System
Initially described by CC Young ( 1937), this genus as a close relative of the originating also from China Euhelopus (then called Helopus ). Even later authors attacked on this hypothesis, this, this genus was often classified within a Euhelopidae mentioned group. Valérie Martin -Rolland (1999) suggested even that Tienshanosaurus could have been identical with Euhelopus. John McIntosh (1990 ) published a short review of the genus and came to the conclusion that the relationships were not sure noticeable. However, he ordered the genus provisionally to the Camarasauridae. The recent study by Toru Sekiya (2011) came to the conclusion that Tienshanosaurus forms a clade together with Mamenchisaurus, Yuanmousaurus and Chuanjiesaurus, the researchers referred to this as Mamenchisauridae. The Mamenchisauridae are thereby classified as a group within the original sauropods Eusauropoda but outside the Neosauropoda.
Research History and naming
The first discovery consisted of two skeletons that were found in close proximity to each other. Since there is no element of the skeleton was present twice, it was assumed that it was a single individual at two findings. The bones found included various cervical and dorsal vertebrae, a caudal vertebra series, chevron bones, the shoulder girdle, pelvis, and various remains of the legs with a. Further, the genus attributed finds included three cervical vertebrae, and 17 tail vertebrae, Dong (1990 ) .. As John McIntosh described announced in 2000, all fossils have been destroyed except for one in 1930 discovered scapula.
The name (in Chinese tian - " sky " in Chinese, shan 'mountain', gr sauros - " lizard" ) means something like "lizard of the celestial mountains" and points to the high Tian Shan Mountains.