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A new transitional sauropodomorph dinosaur from the Early Jurassic of South Africa and the evolution of sauropod feeding and quadrupedalism.
Proc Biol Sci. 2010 Mar 07; 277(1682):787-94.PB

Abstract

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.

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Authors+Show Affiliations

Yates AM
Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, , Johannesburg 2050, South Africa. yatesam@gmail.com
Bonnan MF
No affiliation info available
Neveling J
No affiliation info available
Chinsamy A
No affiliation info available
Blackbeard MG
No affiliation info available

MeSH

AnimalsBehavior, AnimalBiological EvolutionDinosaursFeeding BehaviorFossilsGaitPaleontologySouth Africa

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19906674

Citation

Yates, Adam M., et al. "A New Transitional Sauropodomorph Dinosaur From the Early Jurassic of South Africa and the Evolution of Sauropod Feeding and Quadrupedalism." Proceedings. Biological Sciences, vol. 277, no. 1682, 2010, pp. 787-94.
Yates AM, Bonnan MF, Neveling J, et al. A new transitional sauropodomorph dinosaur from the Early Jurassic of South Africa and the evolution of sauropod feeding and quadrupedalism. Proc Biol Sci. 2010;277(1682):787-94.
Yates, A. M., Bonnan, M. F., Neveling, J., Chinsamy, A., & Blackbeard, M. G. (2010). A new transitional sauropodomorph dinosaur from the Early Jurassic of South Africa and the evolution of sauropod feeding and quadrupedalism. Proceedings. Biological Sciences, 277(1682), 787-94. https://doi.org/10.1098/rspb.2009.1440
Yates AM, et al. A New Transitional Sauropodomorph Dinosaur From the Early Jurassic of South Africa and the Evolution of Sauropod Feeding and Quadrupedalism. Proc Biol Sci. 2010 Mar 7;277(1682):787-94. PubMed PMID: 19906674.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A new transitional sauropodomorph dinosaur from the Early Jurassic of South Africa and the evolution of sauropod feeding and quadrupedalism. AU - Yates,Adam M, AU - Bonnan,Matthew F, AU - Neveling,Johann, AU - Chinsamy,Anusuya, AU - Blackbeard,Marc G, Y1 - 2009/11/11/ PY - 2009/11/13/entrez PY - 2009/11/13/pubmed PY - 2010/4/7/medline SP - 787 EP - 94 JF - Proceedings. Biological sciences JO - Proc Biol Sci VL - 277 IS - 1682 N2 - 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. SN - 1471-2954 UR - https://www.unboundmedicine.com/medline/citation/19906674/A_new_transitional_sauropodomorph_dinosaur_from_the_Early_Jurassic_of_South_Africa_and_the_evolution_of_sauropod_feeding_and_quadrupedalism_ L2 - https://royalsocietypublishing.org/doi/10.1098/rspb.2009.1440?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -