Eucnemesaurus: Research Database
Sauropodomorpha (Dinosauria) · Late Triassic (~215–210 MYA) · Africa — South Africa (Elliot Formation)
Research Note: Eucnemesaurus was a basal sauropodomorph dinosaur from the Late Triassic of South Africa — one of the oldest known dinosaurs from the Elliot Formation and a critical taxon for understanding the early diversification of sauropodomorph dinosaurs in Gondwana. Its name means “true pygmy lizard” — a reference to its relatively small size compared to later sauropods. As a member of the basal sauropodomorph lineage that gave rise to the massive sauropods of the Jurassic, Eucnemesaurus provides important data on the evolutionary transition from small bipedal ancestors to the enormous quadrupedal giants that would dominate the Mesozoic.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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A new phylogenetic and taxonomic framework for basal sauropodomorphs from the Elliot Formation — comprehensive phylogenetic and taxonomic revision of basal sauropodomorphs from the Late Triassic of South Africa, including new data on Eucnemesaurus from the Elliot Formation.
McPhee et al. 2017 provide a comprehensive phylogenetic and taxonomic revision of basal sauropodomorphs from the Late Triassic of South Africa, including new data on Eucnemesaurus, establishing its phylogenetic position, taxonomic validity, and significance for understanding the early diversification of sauropodomorph dinosaurs in Gondwana
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Confirmed | A | 2017 | Fossil | McPhee et al., Acta Palaeontologica Polonica43 citations | Phylogeny |
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New data on basal sauropodomorphs from the Late Triassic of South Africa — additional anatomical and systematic data on Eucnemesaurus and related basal sauropodomorphs from the Late Triassic of South Africa, clarifying their relationships and diversity.
Galton & Yates 2007 provide additional anatomical and systematic data on basal sauropodomorphs from the Late Triassic of South Africa, including Eucnemesaurus, documenting new referred specimens and clarifying the taxonomy and relationships of these early dinosaurs from the South African Elliot Formation
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Confirmed | B | 2007 | Fossil | Galton & Yates, Neues Jahrbuch für Geologie und Paläontologie28 citations | Systematics |
Active Debate: Basal Sauropodomorph Diversity in the Late Triassic of Gondwana
Whether the diversity of basal sauropodomorphs in the Late Triassic of Gondwana reflects a genuine adaptive radiation or sampling bias is debated. Eucnemesaurus and other basal sauropodomorphs from the Elliot Formation represent some of the oldest known dinosaurs from southern continents, but the fragmentary nature of many specimens makes taxonomic and phylogenetic conclusions uncertain.
What We Still Do not Know About Eucnemesaurus
- Colouration: Completely unknown.
- Complete skeleton: Known from fragmentary material.
- Diet: Inferred from dental anatomy; no stomach contents known.
- Growth series: No juvenile specimens known.
- Social structure: No direct evidence.
In Depth
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.
