Tags

Type your tag names separated by a space and hit enter

A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs.
Curr Biol. 2018 10 08; 28(19):3143-3151.e7.CB

Abstract

Sauropod dinosaurs were dominant, bulk-browsing herbivores for 130 million years of the Mesozoic, attaining gigantic body masses in excess of 60 metric tons [1, 2]. A columnar-limbed, quadrupedal posture enabled these giant body sizes [3], but the nature of the transition from bipedal sauropodomorph ancestors to derived quadrupeds remains contentious [4-6]. We describe a gigantic, new sauropodomorph from the earliest Jurassic of South Africa weighing 12 metric tons and representing a phylogenetically independent origin of sauropod-like body size in a non-sauropod. Osteohistological evidence shows that this specimen was an adult of maximum size and approximately 14 years old at death. Ledumahadi mafube gen. et sp. nov. shows that gigantic body sizes were possible in early sauropodomorphs, which were habitual quadrupeds but lacked the derived, columnar limb postures of sauropods. We use data from this new taxon and a discriminant analysis of tetrapod limb measurements to study postural evolution in sauropodomorphs. Our results show that quadrupedality appeared by the mid-Late Triassic (Norian), well outside of Sauropoda. Secondary reversion to bipedality occurred in some lineages phylogenetically close to Sauropoda, indicating early experimentation in locomotory styles. Morphofunctional observations support the hypothesis that partially flexed (rather than columnar) limbs characterized Ledumahadi and other early-branching quadrupedal sauropodomorphs. Patterns of locomotory and body-size evolution show that quadrupedality allowed Triassic sauropodomorphs to achieve body sizes of at least 3.8 metric tons. Ledumahadi's Early Jurassic age shows that maximum body mass in sauropodomorph dinosaurs was either unaffected or rapidly rebounded after the end-Triassic extinction event.

Authors+Show Affiliations

Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brasil; Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa; Department of Earth Sciences, University of Oxford, Oxford, UK.National Museum, Bloemfontein, South Africa; Department of Zoology and Entomology, University of the Free State, Bloemfontein, Bloemfontein, South Africa 9300.Department of Geological Sciences, University of Cape Town, Cape Town, South Africa.Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa. Electronic address: jonah.choiniere@wits.ac.za.

Pub Type(s)

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

Language

eng

PubMed ID

30270189

Citation

McPhee, Blair W., et al. "A Giant Dinosaur From the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs." Current Biology : CB, vol. 28, no. 19, 2018, pp. 3143-3151.e7.
McPhee BW, Benson RBJ, Botha-Brink J, et al. A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. Curr Biol. 2018;28(19):3143-3151.e7.
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 : CB, 28(19), 3143-e7. https://doi.org/10.1016/j.cub.2018.07.063
McPhee BW, et al. A Giant Dinosaur From the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. Curr Biol. 2018 10 8;28(19):3143-3151.e7. PubMed PMID: 30270189.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. AU - McPhee,Blair W, AU - Benson,Roger B J, AU - Botha-Brink,Jennifer, AU - Bordy,Emese M, AU - Choiniere,Jonah N, Y1 - 2018/09/27/ PY - 2018/04/08/received PY - 2018/05/30/revised PY - 2018/07/24/accepted PY - 2018/10/3/pubmed PY - 2019/10/23/medline PY - 2018/10/2/entrez KW - body size KW - columnar limbs KW - gigantism KW - posture SP - 3143 EP - 3151.e7 JF - Current biology : CB JO - Curr Biol VL - 28 IS - 19 N2 - Sauropod dinosaurs were dominant, bulk-browsing herbivores for 130 million years of the Mesozoic, attaining gigantic body masses in excess of 60 metric tons [1, 2]. A columnar-limbed, quadrupedal posture enabled these giant body sizes [3], but the nature of the transition from bipedal sauropodomorph ancestors to derived quadrupeds remains contentious [4-6]. We describe a gigantic, new sauropodomorph from the earliest Jurassic of South Africa weighing 12 metric tons and representing a phylogenetically independent origin of sauropod-like body size in a non-sauropod. Osteohistological evidence shows that this specimen was an adult of maximum size and approximately 14 years old at death. Ledumahadi mafube gen. et sp. nov. shows that gigantic body sizes were possible in early sauropodomorphs, which were habitual quadrupeds but lacked the derived, columnar limb postures of sauropods. We use data from this new taxon and a discriminant analysis of tetrapod limb measurements to study postural evolution in sauropodomorphs. Our results show that quadrupedality appeared by the mid-Late Triassic (Norian), well outside of Sauropoda. Secondary reversion to bipedality occurred in some lineages phylogenetically close to Sauropoda, indicating early experimentation in locomotory styles. Morphofunctional observations support the hypothesis that partially flexed (rather than columnar) limbs characterized Ledumahadi and other early-branching quadrupedal sauropodomorphs. Patterns of locomotory and body-size evolution show that quadrupedality allowed Triassic sauropodomorphs to achieve body sizes of at least 3.8 metric tons. Ledumahadi's Early Jurassic age shows that maximum body mass in sauropodomorph dinosaurs was either unaffected or rapidly rebounded after the end-Triassic extinction event. SN - 1879-0445 UR - https://www.unboundmedicine.com/medline/citation/30270189/A_Giant_Dinosaur_from_the_Earliest_Jurassic_of_South_Africa_and_the_Transition_to_Quadrupedality_in_Early_Sauropodomorphs_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0960-9822(18)30993-X DB - PRIME DP - Unbound Medicine ER -