Eucnemesaurus
Name:
Eucnemesaurus
(Good tibia lizard).
Phonetic: Yew-nem-e-sore-us.
Named By: Egbert Cornelis Nicolaas van Hoepen -
1920.
Synonyms: Aliwalia.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Sauropodomorpha, Prosauropoda, Riojasauridae.
Species: E. fortis (type), E. entaxonis .
Diet: Herbivore?
Size: Unavailable.
Known locations: South Africa, Orange Free State
- Lower Elliot Formation.
Time period: Carnian/Norian of the Triassic.
Fossil representation: Partial remains from at least
three individuals.
In
simple terms Eucnemesaurus was a prosauropod, a
member of the group
that was ancestral to the later larger sauropods. Eucnemesaurus
has a
better know association with a former dinosaur genus Aliwalia.
Aliwalia was big news when described, even though
it was only
described from a femur and a partial maxilla. The maxilla was clearly
that of a theropod, and with the large femur, this theropod was
roughly estimated to have been around eight meters long. At the time
this made Aliwalia the first of the large meat
eating dinosaurs,
comparable even to large late Jurassic predators such as Allosaurus.
Later
study would however dispel the notion of a large dinosaurian predator
stomping around South Africa during the late Triassic. The femur is
not only that of a prosauropod dinosaur, but it is a match for
material that was earlier described as Eucnemesaurus.
This presents
the problem of the carnivore maxilla, but the simple explanation is
that the two bones are not of the same animal. This means that when
Aliwalia was described it was essentially a fossil
chimera, a
collection of remains from more than one type of creature mistakenly
described as one. The maxilla of a carnivore may be from a dinosaur
that died while feeding upon the body of a Eucnemesaurus,
or it could
have simply been deposited in association to it by scattering or
washing.
Eucnemesaurus
is currently regarded as being a member of the Riojasauridae, meaning
that it is considered to be similar to Riojasaurus.
Further reading
- Contributions to the knowledge of the reptiles of the Karroo
Formation. 6. Further dinosaurian material in the Transvaal Museum. -
Annals of the Transvaal Museum 7(2):93-141. - E. C. N. Van Hoepen -
1920.
- Solving a dinosaurian puzzle: the identity of Aliwalia rex
Galton. - Adam M. Yates - 2006.
- A second species of Eucnemesaurus Van Hoepen,
1920 (Dinosauria,
Sauropodomorpha): new information on the diversity and evolution of the
sauropodomorph fauna of South Africa's lower Elliot Formation (latest
Triassic). - Journal of Vertebrate Paleontology 35(5):e980504:1-24. -
B. W. McPhee, J. N. Choiniere, A. M. Yates & P. A. Viglietti -
2015.
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