Eucoelophysis

Taxobox
name = "Eucoelophysis"
fossil_range = Late Triassic
regnum = Animalia
phylum = Chordata
classis = Sauropsida
infraclassis = Archosauromorpha
unranked_ordo = Ornithodira
unranked_familia = Dinosauriformes
genus = "Eucoelophysis"
binomial = "Eucoelophysis baldwini"
binomial_authority = Sullivan & Lucas, 1999

"Eucoelophysis" (meaning "true hollow tail") is a genus of dinosauriform from the Late Triassic (Norian) period of New Mexico. It was assumed to be a coelophysid upon description, but a 2005 study by Nesbitt "et al." found that it was actually a close relative of "Silesaurus", which was independently supported by Ezcurra (2006), who found it to be the sister group to Dinosauria, and "Silesaurus" as the next most basal taxon.Sullivan, R.M. and Lucas, S.G. (1999). "Eucoelophysis baldwini", a new theropod dinosaur from the Upper Triassic of New Mexico, and the status of the original types of Coelophysis". "Journal of Vertebrate Paleontology" 19(1): 81-90.] Nesbitt, S.J., Irmis, R.B., and Parker, W.G. (2005). "A critical review of the Triassic North American dinosaur record." In Kellner, A.W.A., Henriques, D.D.R., & Rodrigues, T. (eds.), "II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos." Rio de Janeiro: Museum Nacional/UFRJ, 139.] Ezcurra, M.D. (2006). "A review of the systematic position of the dinosauriform archosaur "Eucoelophysis baldwini" Sullivan & Lucas, 1999 from the Upper Triassic of New Mexico, USA." "Geodiversitas", 28(4):649-684.]

However, the relationships of "Silesaurus" are uncertain. Dzik found it to be a dinosauriform (the group of archosaurs from which the dinosaurs evolved), but did not rule out the possibility that it represents a primitive ornithischian.Dzik, J. (2003). "A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland." "Journal of Vertebrate Paleontology", 23(3): 556-574.]

References

External links

* [http://www.mnhn.fr/museum/front/medias/publication/9255_g06n4a5.pdf PDF of Ezcurra (2006)]
* [http://dml.cmnh.org/2007Jan/msg00017.html William Parker's reaction to Ezcurra (2006)] , from the Dinosaur Mailing List.