Open Paleo

Antetonitrus

Yates & Kitching, 2003 an-TEE-toh-NIGH-trus

From Latin 'ante' meaning 'before' and 'tonitrus' meaning 'thunder', meaning 'before thunder', referring to its existence before Brontosaurus (the 'thunder lizard').

201.4–192.9 million years ago Hettangian–Sinemurian, Early Jurassic
Early Jurassic stages

Antetonitrus is a genus of sauropodiform dinosaur found in the Early Jurassic Elliot Formation of South Africa. The only species is Antetonitrus ingenipes. Sometimes considered a basal sauropod, it is crucial for the understanding of the origin and early evolution of this group. It was a quadrupedal herbivore, like its later relatives, but shows primitive adaptations to use the forelimbs for grasping, instead of purely for weight support.

Diagnosis

  1. Dorsal neural spines flared transversely at their distal end.
  2. Dorsal vertebrae with broad, triangular hyposphenes in caudal view.
  3. Ventral ridge on the hyposphenes of the caudal dorsal vertebrae.
  4. Deep sulcus adjacent to the lateral distal margin of the deltopectoral crest.
  5. Extremely short, broad metacarpal I (maximum length only 85% of proximal width).

Species

Antetonitrus ingenipes Yates & Kitching, 2003

Type species

From Latin ingens, meaning 'massive', and pes, meaning 'foot', because it shows the beginning of the development of feet designed solely to support weight.

Holotype
BP/1/4952 , Evolutionary Studies Institute (formerly Bernard Price Institute for Palaeontological Research), University of the Witwatersrand
Material
Partial disarticulated skeleton including cervical centrum, four dorsal vertebrae, sacral vertebra, caudal vertebrae, dorsal ribs, chevrons, scapulae, right humerus, both ulnae, left radius, left metacarpal I, both metacarpals II, left manual phalanx I1, two ?manual unguals, left pubis, left femur, left tibia, left fibula, left and right metatarsals, two pedal phalanges, pedal unguals.
Horizon
upper Elliot Formation, Hettangian–Sinemurian, Early Jurassic , 201.4–192.9 million years ago
Locality
Welbedacht (611)/Edelweiss (698), Free State, South Africa Yates and Kitching (2003) described it from "the Upper Triassic (Norian) sediments of South Africa"; McPhee and colleagues (2018) treat it as an upper Elliot Formation taxon, among the Early Jurassic sauropodomorphs.

References

  1. Yates, A. M.; Kitching, J. W. (2003). The earliest known sauropod dinosaur and the first steps towards sauropod locomotion. Proceedings of the Royal Society of London. Series B: Biological Sciences 270(1525): 1753-1758. The Royal Society. doi:10.1098/rspb.2003.2417 yates2003a
  2. McPhee, B. W.; Benson, R. B. J.; Botha-Brink, J.; Bordy, E. M.; Choiniere, J. N. (2018). A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. Current Biology 28(19): 3143-3151.e7. Elsevier BV. doi:10.1016/j.cub.2018.07.063

    Treats Antetonitrus as an upper Elliot Formation taxon, sister to Ledumahadi.

    mcphee2018a