Eucnemesaurus

From Wikipedia, the free encyclopedia

Eucnemesaurus
Fossil range: Late Triassic

Extinct (fossil)

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Sauropodomorpha
Family:	Riojasauridae
Genus:	Eucnemesaurus
Species:	E. fortis

Binomial name

Eucnemesaurus fortis
Hoepen, 1920

Synonyms

Aliwalia Galton, 1985

Eucnemesaurus (IPA: /jukˌnimɪˈsɔɹəs/;"good tibia lizard", for its robust tibiae) is a basal sauropodomorph usually considered to be a synonym of Euskelosaurus, but recent study by Yates (2006) indicates that it is valid and the same animal as putative "giant herrerasaurid" Aliwalia. It is based on a partial skeleton including vertebrae, part of a pubis, a femur, and two tibiae. The remains were found in the late Carnian-early Norian-age Upper Triassic Lower Elliot Formation of the Slabberts district, Orange Free State, South Africa.

Yates assigned the genus to the new family Riojasauridae, with Riojasaurus, usually regarded as a melanorosaurid.

[edit] History

Fossil material now assigned to Eucnemesaurus was once placed in a separate genus, Aliwalia rex (the generic name was taken from the Aliwal Park Reserve in the Union of South Africa, where the first remains were found). The fossil evidence of this species was comparably small, with for many years only femoral fragments and a maxilla known.

For many years the size of the femur lead many palaeontologists to believe (along with the clearly carnivorous maxilla), that Aliwalia was a carnivorous dinosaur of remarkable size for the age in which lived. It would have been comparable to that of the large Jurassic and Cretaceous theropods, such as Allosaurus, that evolved tens of millions of years after Aliwalia. The original material was believed to bear a strong similarity to the South American Herrerasaurus, so much so that Aliwalia was originally classified in Herrerasauridae by Peter Malcolm Galton.

However, recent re-evaluation of the material has shown that the maxilla assigned to Aliwalia does not, unlike the other material, belong to Eucnemesaurus, as it is clearly from a carnivore. In addition, new material clearly demonstrates this species sauropodomorph affinites (and that it belongs to E. fortis).