Chuandongocoelurus

• Chuandong, Sichuan, People's Republic of China ( Dashanpu Formation)

• Chuandongocoelurus Primitivus

Chuandongocoelurus small theropod dinosaurs is a genus from the group of Tetanurae. The only way is Chuandongocoelurus Primitivus. This genus is based on a fragmentary skeleton, which in the strata of Middle Jurassic Dashanpu Formation ( Bathonian to Callovian ) in Sichuan (China) was discovered. On the fossils no unique features ( autapomorphies ) could be identified, but which are essential to distinguish this species from other genera and why Chuandongocoelurus is now run as a noun dubium.

The name Chuandongocoelurus ( Chuandong, gr koilos - " hollow", oura - " dick ") means as much as " hollow tail Chuandong ". The name refers to the locality Chuandong in the Chinese province of Sichuan, as well as on the Coelurosauria ( " hollow tails" ), which this dinosaur was initially attributed.

Description and references

The fossils found are compared with those of other theropods very small, so the body weight of this individual is estimated to be only 13-14 kilograms. The thigh bone (femur) measures just 20.5 centimeters in length. Show not yet fused Rückenwirbelsuturen that it was not yet a full-grown animal. If you used to scale the femurs of Elaphrosaurus, one can estimate the length of the holotype to 2.4 m. The skeleton shows an interesting combination of derived ( synapomorphies of Tetanurae ) and basal characteristics.

The skeleton ( holotype, specimen number CCG 20010 ) consists among other things of some neck (including third cervical vertebra ( 61 mm ) and tenth cervical vertebra ( 69 mm ) ), dorsal and caudal vertebrae ( 60 mm), an incomplete shoulder blade (scapula ) ( 288 mm long), incomplete pelvic bone ( ilium ( ilium ), pubic bone ( pubis ) and ischial ( ischium ) ), leg bones (thigh bone (femur), shinbone ( tibia) (231 mm long), fibula ( fibula ) ) and foot bones ( including anklebone ( astragalus ) and calcaneus ( calcaneum ) and toe bones and finger bones). Skull bones are not known.

He Xinluhai has a much larger individual described ( CCG 20011; known by eddy ) to be related, but this shows a few similarities with the holotype, and seems rather Elaphrosaurus.

Classification

There are authors who believe that Chuandongocoelurus primtivus was an ornithopod, but this is very unlikely, because the shape of the tibia shows a few similarities with that of ornithopods. The shape of the ilium also points rather to a member of the Tetanurae. However, the shape of the femoral head is not typical for members of the Tetanurae group. Chuandongocoelurus primtivus also has a comb shape, of which one believes that it is not among members of the group Tetanurae ( Holtz 2000), but in 2010, Zhao and others have found prove that Monolophosaurus had a similar comb shape. In the same year Benson have classified, among other things this animal as a sister genus of Monolophosaurus. He Xinluhai has classified these theropods as related by Coelurus. Holtz (1994 ) classified it as a relative of Elaphrosaurus, both he classified as Abelisauriden.