Thursday, December 31, 2015

The Giving of December. Eucnemesaurus

    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.

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