Tienshanosaurus

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Tienshanosaurus
Temporal occurrence
Upper Jurassic ( Oxfordium )
163.5 to 157.3 million years
Locations
Systematics
Dinosaur (dinosauria)
Lizard dinosaur (Saurischia)
Sauropodomorpha
Sauropods (Sauropoda)
Tienshanosaurus
Scientific name
Tienshanosaurus
CC Young , 1937
Art
  • Tienshanosaurus chitaiensis Young, 1937

Tienshanosaurus is a little known genus of sauropod dinosaur from the Upper Jurassic of China . It was first described scientificallyby CC Young (Yang Zhongjian)in 1937, making it - after Euhelopus - the second described sauropod to be discovered in China. The first description was based on a skullless skeleton that came from the Shishugou Formation in the Chinese autonomous region of Xinjiang andcould be datedto the Oxfordium . Later other finds were assigned to the genus. Today, all finds have been destroyed except for a shoulder blade discovered in 1930.

It is unclear to which group within the sauropods this genus belongs, although the latest study suggests a classification within the Mamenchisauridae . Some researchers currently regard the genus as the noun dubium (genus with dubious validity), as no characteristics are known which clearly differentiate the genus from other genera. The only species in the genus is Tienshanosaurus chitaiensis .

features

As with all sauropods, it was a four-legged herbivore with a long neck and tail. Tienshanosaurus was a relatively small sauropod - Youg (1937) estimated the first specimen found to be around 10 meters long. Compared to other sauropods, the cervical vertebrae were relatively short and had thin cervical ribs that protruded backwards beyond the posterior edge of the vertebral body . The posterior vertebrae were characterized by weak lateral cavities (pleurocoels), while these were absent in the caudal vertebrae. The posterior vertebrae and the caudal vertebrae were amphicoel (concave on the front and back). The shoulder blade had a long stem and a wide proximal (front) end, the coracoid (coracoid) was small. The humerus was relatively slender, while the iliac bone was short and high.

Systematics

Initially, CC Young (1937) described this genus as a close relative of the Euhelopus (then referred to as Helopus ), also from China . Later authors also took up this hypothesis, and this genus was often classified within a group called Euhelopidae . Valérie Martin-Rolland (1999) suggested even that tienshanosaurus with euhelopus could have been identical. John McIntosh (1990) published a brief review of the genus and came to the conclusion that the relationships could not be determined with certainty. However, he provisionally assigned the genus to the Camarasauridae . The most recent study by Toru Sekiya (2011) found that Tienshanosaurus forms a clade with Mamenchisaurus , Yuanmousaurus and Chuanjiesaurus , which this researcher calls Mamenchisauridae . The Mamenchisauridae are classified as a group of original sauropods within the Eusauropoda , but outside the Neosauropoda .

Research history and naming

The first find consisted of two skeletal parts that were found in close proximity to each other. Since no element of the skeleton was duplicated, it was assumed that both finds were a single individual. The bones found included various cervical and dorsal vertebrae, a series of caudal vertebrae, chevron bones , the shoulder girdle, the pelvis, and various remains of the legs. Other finds attributed to the genus included three cervical vertebrae and 17 caudal vertebrae, which were described by Dong (1990). As John McIntosh announced in 2000, all but one shoulder blade discovered in 1930 has been destroyed.

The name ( Chinese tian - "sky", Chinese shan "mountain", Greek sauros - "lizard") means something like "lizard of the heavenly mountains" and refers to the high mountains of Tian Shan .

Individual evidence

  1. ↑ a b c d e f g John S. McIntosh: Sauropoda. In: David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . University of California Press, Berkeley CA et al. 1990, ISBN 0-520-06726-6 , pp. 345-401, here p. 387.
  2. ^ A b c Donald F. Glut : Dinosaurs. The Encyclopedia. Supplement 2. McFarland, Jefferson NC 2002, ISBN 0-7864-1166-X , pp. 334-335.
  3. ↑ a b c Toru Sekiya: Re-examination of Chuanjiesaurus anaensis (Dinosauria: Sauropoda) from the Middle Jurassic Chuanjie Formation, Lufeng County, Yunnan Province, Southwest China. In: Memoir of the Fukui Prefectural Dinosaur Museum. No. 10, 2011, ISSN  1347-5622 , pp. 1–54, here p. 29, digital version (PDF; 9.26 MB) .
  4. ^ Paul Upchurch , Paul M. Barrett , Peter Dodson: Sauropoda. In: David B. Weishampel, Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 259-324, here p. 271.
  5. ^ A b c Donald F. Glut: Dinosaurs. The Encyclopedia. McFarland, Jefferson NC et al. 1997, ISBN 0-89950-917-7 , pp. 907-908.
  6. ^ Tienshanosaurus - Taxonomy. In: The Paleobiology Database. Retrieved August 21, 2014 .
  7. ↑ Ben Creisler: Dinosauria Translation and Pronunciation Guide ( Memento of October 13, 2011 in the Internet Archive )