[D] Aardonyx celestae [Su] [sG] [T]
Describer
Yates, Bonnan, Neveling, Chinsamy and Blackbeard 2009
Time
Jurassic Early Hettangian Sinemurian Pliensbachian Toarcian
Classification
Saurischia Sauropodomorpha
Diet
Herbivorre
Fossilsite
Upper Elliot Formation, ´Marc’s Quarry´ Spion Kop farm, Senekal District, Orange Free State, South Africa
Length
7 meter in length
Info
Based on bones of two individuals thoroughly comingled. The major missing elements were the nasal and quadrate bones of the skull, the humerus of the forelimb and the ilium of the pelvis.
Aardonyx celestae gen. et sp. nov. is described from the upper Elliot Formation (Early Jurassic) of South Africa. It can be diagnosed by autapomorphies of the skull, particularly the jaws, cervical column, forearm and pes. It is found to be the sister group of a clade of obligatory quadrupedal sauropodomorphs (Melanorosaurus + Sauropoda) and thus lies at the heart of the basal sauropodomorph-sauropod transition.
The narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks. Broad, U-shaped jaws were previously thought to have evolved prior to the loss of gape-restricting cheeks. However, the narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks, demonstrating unappreciated homoplasy in the evolution of the sauropod bulk-browsing apparatus.
The limbs of A. celestae indicate that it retained a habitual bipedal gait although incipient characters associated with the pronation of the manus and the adoption of a quadrupedal gait are evident through geometric morphometric analysis (using thin-plate splines) of the ulna and femur. Cursorial ability appears to have been reduced and the weight bearing axis of the pes shifted to a medial, entaxonic position, falsifying the hypothesis that entaxony evolved in sauropods only after an obligate quadrupedal gait had been adopted.
Yates, Bonnan, Neveling, Chinsamy and Blackbeard 2009
Time
Jurassic Early Hettangian Sinemurian Pliensbachian Toarcian
Classification
Saurischia Sauropodomorpha
Diet
Herbivorre
Fossilsite
Upper Elliot Formation, ´Marc’s Quarry´ Spion Kop farm, Senekal District, Orange Free State, South Africa
Length
7 meter in length
Info
Based on bones of two individuals thoroughly comingled. The major missing elements were the nasal and quadrate bones of the skull, the humerus of the forelimb and the ilium of the pelvis.
Aardonyx celestae gen. et sp. nov. is described from the upper Elliot Formation (Early Jurassic) of South Africa. It can be diagnosed by autapomorphies of the skull, particularly the jaws, cervical column, forearm and pes. It is found to be the sister group of a clade of obligatory quadrupedal sauropodomorphs (Melanorosaurus + Sauropoda) and thus lies at the heart of the basal sauropodomorph-sauropod transition.
The narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks. Broad, U-shaped jaws were previously thought to have evolved prior to the loss of gape-restricting cheeks. However, the narrow jaws of A. celestae retain a pointed symphysis but appear to have lacked fleshy cheeks, demonstrating unappreciated homoplasy in the evolution of the sauropod bulk-browsing apparatus.
The limbs of A. celestae indicate that it retained a habitual bipedal gait although incipient characters associated with the pronation of the manus and the adoption of a quadrupedal gait are evident through geometric morphometric analysis (using thin-plate splines) of the ulna and femur. Cursorial ability appears to have been reduced and the weight bearing axis of the pes shifted to a medial, entaxonic position, falsifying the hypothesis that entaxony evolved in sauropods only after an obligate quadrupedal gait had been adopted.