|Skeletal diagram showing known remains|
Discovery and namingEdit
The type species Chuandongocoelurus primitivus was first described and named by Chinese paleontologist He Xinlu in 1984. The generic name combines references to the Chuandong in Sichuan Province and the theropod genus Coelurus, itself named after the Greek κοῖλος, koilos, meaning "hollow" and οὐρά, oura, meaning "tail". The specific name means "the primitive one" in Latin, a reference to the great age of the find.
Chuandongocoelurus was initially based on two partial skeletons. The holotype, a thighbone, is part of specimen CCG 20010. Vertebrae, pelvic bones and hindlimb elements, also catalogued under this inventory number, may belong to the same individual. The specimen has unfused neurocentral sutures in its vertebrae, meaning that the animal was immature at the time of death. The formation in which it was discovered was the Lower Shaximiao Formation, part of the Dashanpu Formation, meaning Chuandongocoelurus dates to the Bathonian or Callovian stage of the Middle Jurassic. A second specimen is CCG 20011, a set of neck vertebrae from a different and much larger individual. In 2012, it was concluded that both specimens represent different taxa, probably not even closely related. With CCG 20011 being a close relative of Elaphrosaurus
The holotype thighbone has a length of 201 millimetres.
He placed Chuandongocoelurus in the Coeluridae, at the time a wastebasket taxon including almost all small theropods. David Bruce Norman in 1990 considered it to be an indeterminate theropod. More recently, Roger Benson (2008, 2010) and Benson et alii (2010) found it to be the sister taxon of Monolophosaurus, together forming a clade belonging either to Megalosauroidea or outside of Megalosauroidea in the Tetanurae. In 2012, Matthew Carrano e.a. found Chuandongocoelurus outside of the Megalosauria.
- He, 1984. The vertebrate fossils of Sichuan. Sichuan Scientific and Technological Publishing House. 168 pp.
- M.T. Carrano, R.B.J. Benson, and S.D. Sampson, 2012, "The phylogeny of Tetanurae (Dinosauria: Theropoda)", Journal of Systematic Palaeontology 10(2): 211-300
- Norman, David B. (1990). Problematic Theropoda: "Coelurosaurs". p. 280-305 in David B. Weishampel, et al. (eds.), The Dinosauria. University of California Press, Berkeley, Los Angeles, Oxford.
- Benson, 2008. A new theropod phylogeny focussing on basal tetanurans, and its implications for European 'megalosaurs' and Middle Jurassic dinosaur endemism. Journal of Vertebrate Paleontology. 51A
- Benson, R.B.J. (2010). "A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods". Zoological Journal of the Linnean Society. 158 (4): 882–935. doi:10.1111/j.1096-3642.2009.00569.x.
- Benson, Brusatte and Carrano, 2010. A new clade of large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic. Naturwissenschaften. 97, 71-78