Chuandongocoelurus

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Chuandongocoelurus
Bones of the only known, juvenile individual highlighted

Bones of the only known, juvenile individual highlighted

Temporal occurrence
Middle Jurassic ( Bathonian to Callovian )
168.3 to 163.5 million years
Locations
Systematics
Ornithodira
Dinosaur (dinosauria)
Lizard dinosaur (Saurischia)
Theropoda
Tetanurae
Chuandongocoelurus
Scientific name
Chuandongocoelurus
Hey , 1984
Art
  • Chuandongocoelurus primitivus

Chuandongocoelurus is a genus of small theropod dinosaurs belonging to the Tetanurae group . The only species is Chuandongocoelurus primitivus . This genus is based on a fragmentary skeleton that was discovered in the strata of the Central Jurassic Dashanpu Formation ( Bathonium to Callovium ) in Sichuan ( China ). No unique features ( autapomorphies ) could be identifiedon the fossils,but these are essential to distinguish this genus from other genera and which is why Chuandongocoelurus is now listed as a noun dubium .

The name Chuandongocoelurus (Chuandong, Greek koilos - "hollow", oura - "tail") means something like "hollow tail from Chuandong". The name points to the place where they were found Chuandong in the Chinese province of Sichuan and to the Coelurosauria ("hollow tails"), to which this dinosaur was initially ascribed.

Description and find

The fossils found are very small compared to those of other theropods, so the body weight of this individual is estimated at only 13-14 kilograms. The thigh bone (femur) is only 20.5 centimeters long. Vertebral sutures that have not yet fused show that the animal was not yet fully grown. Using the Elaphrosaurus thigh bone for scaling, the length of the holotype can be estimated to be 2.4 m. The skeleton shows an interesting combination of derived (synapomorphies of the tetanurae) and basal features.

The skeleton (holotype, copy number CCG 20010) consists of some cervical (including third cervical vertebrae (61 mm) and tenth cervical vertebrae (69 mm)), dorsal and tail vertebrae (60 mm), an incomplete shoulder blade (scapula) ( 288 mm long), incomplete pelvic bone ( iliac (ilium), pubis (pubic) and the seat leg (ischium)), leg bone ( thigh bone (femur), tibia (tibia) (231 mm long), fibula (fibula)) and foot bones (including Ankle bone (astragalus) and heel bone (calcaneum) as well as toe bones and finger bones). No skull bones are known.

He Xinlu described a much larger individual (CCG 20011; known from vertebrae), but this one shows little in common with the holotype and appears to be more related to 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 little in common with that of ornithopods. The shape of the iliac bone also suggests a member of the Tetanurae. However, the shape of the femoral head is atypical for members of the tetanurae. Chuandongocoelurus primtivus also has a comb shape that is believed not to belong to the Tetanurae group (Holtz 2000), but in 2010 Zhao et al. Evidence found that Monolophosaurus had a similar comb shape. In the same year, Benson et al. this animal is classified as a sister genus of Monolophosaurus . He Xinlu has classified this theropod as a relative of Coelurus . Holtz (1994) classified him as a relative of Elaphrosaurus , both of which he classified as Abelisaurids .

Individual evidence

  1. a b c d e f Details on Chuandongocoeluros
  2. ^ A b c Matthew T. Carrano, Roger BJ Benson, Scott D. Sampson: The phylogeny of Tetanurae (Dinosauria: Theropoda). In: Journal of Systematic Palaeontology. Vol. 10, No. 2, 2012, ISSN  1477-2019 , pp. 211-300, here p. 233, doi : 10.1080 / 14772019.2011.630927 .
  3. Thomas R. Holtz Jr. , Ralph E. Molnar, Philip J. Currie : Basal Tetanurae. 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. 71-110.
  4. ^ A b David B. Norman : Problematic Theropoda: "Coelurosaurs". In: David B. Weishampel, Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 1990, ISBN 0-520-06726-6 , pp. 280-305.
  5. Ben Creisler: Dinosauria Translation and Pronunciation Guide C. (No longer available online.) Archived from the original on December 12, 2015 ; Retrieved November 20, 2011 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.dinosauric.com
  6. a b Stephen L. Brusatte, Roger BJ Benson, Xing Xu: The evolution of large-bodied theropod dinosaurs during the Mesozoic in Asia. In: Journal of Iberian Geology. Vol. 36, No. 2, 2010, ISSN  1698-6180 , pp. 275-296, online .
  7. The Theropod Database ( Memento of the original from September 29, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , English.  @1@ 2Template: Webachiv / IABot / archosaur.us
  8. Oliver WM Rauhut : The interrelationships and evolution of basal theropod dinosaurs (= Special Papers in Palaeontology. Vol. 69). The Palaeontological Association, London 2003, ISBN 0-901702-79-X .
  9. Thomas R. Holtz Jr .: A new phylogeny of the carnivorous dinosaurs. In: Gaia. Revista de Geociências. Vol. 15, 2000, ISSN  0871-5424 , pp. 5-61. online (PDF; 833.15 kB) .
  10. Xin-Jin Zhao, Roger BJ Benson, Stephen L. Brusatte, Philip J. Currie: The postcranial skeleton of Monolophosaurus jiangi (Dinosauria: Theropoda) from the Middle Jurassic of Xinjiang, China, and a review of Middle Jurassic Chinese theropods. In: Geological Magazine. Vol. 147, No. 1, 2010, ISSN  0016-7568 , pp. 13-27, doi : 10.1017 / S0016756809990240 .
  11. ^ Roger BJ Benson: A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. In: Zoological Journal of the Linnean Society. Vol. 158, No. 4, 2010, ISSN  0024-4082 , pp. 882-935, doi : 10.1111 / j.1096-3642.2009.00569.x .