Eucnemesaurus

Taxobox
name = "Eucnemesaurus"
fossil_range = Late Triassic
regnum = Animalia
phylum = Chordata
classis = Sauropsida
superordo = Dinosauria
ordo = Saurischia
subordo = Sauropodomorpha
infraordo = Prosauropoda
familia = Riojasauridae
genus = "Eucnemesaurus"
species = "E. fortis"
binomial = "Eucnemesaurus fortis"
binomial_authority = Hoepen, 1920
synonyms =
* "Aliwalia" Galton, 1985

"Eucnemesaurus" (pronEng|juːkˌniːmɨˈsɔrəs; meaning "good tibia lizard", for its robust tibiae) is a basal sauropodomorph dinosaur genus usually considered to be a synonym of "Euskelosaurus". Recent study by Yates (2006), however, 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.

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 led 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 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 genus' sauropodomorph affinities.

References

* Yates, A.M. (2006). "Solving a dinosaurian puzzle: the identity of "Aliwalia rex" Galton". "Historical Biology", 1–31, iFirst article

External links

* [http://www.users.qwest.net/~jstweet1/sauropodomorpha.htm Sauropodomorpha]