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Data for: Africa’s oldest dinosaurs reveal early climatic suppression of dinosaurian distribution

Citation

Griffin, Christopher et al. (2022), Data for: Africa’s oldest dinosaurs reveal early climatic suppression of dinosaurian distribution, Dryad, Dataset, https://doi.org/10.5061/dryad.pg4f4qrqd

Abstract

The vertebrate lineages that would shape Mesozoic and Cenozoic terrestrial ecosystems originated within faunas across Triassic Pangaea1-11. By the Late Triassic (Carnian Stage, ~235 Ma), cosmopolitan ‘disaster faunas’12-14 had given way to highly endemic assemblages12,13 on the supercontinent. Testing the tempo and mode of the establishment of this endemism is challenging—paradoxically, there were few geographic barriers to dispersal across Pangaea during the Late Triassic. Instead, palaeolatitudinal climate belts, and not continental boundaries, are hypothesized to have controlled biogeography15-18. During this time of high endemism, dinosaurs began to disperse and thus offer an opportunity to test the timing and drivers of this biogeographic pattern. Increased sampling can test this prediction: if dinosaurs initially dispersed under palaeolatitudinal-driven endemism, then an assemblage similar to those of South America4,19-21 and India19,22—including the earliest dinosaurs—should be present in Carnian deposits along the same palaeolatitude in south-central Africa. Here, we report a new Carnian assemblage from Zimbabwe which includes Africa’s oldest definitive dinosaurs, including a nearly complete (~90%), exceptionally preserved skeleton of the early sauropodomorph Mbiresaurus raathi, gen. et sp. nov. This assemblage greatly resembles those of other dinosaur-bearing Carnian assemblages and includes herrerasaurid dinosaurs, rhynchosaurs, cynodonts, and aetosaurs, suggesting that a similar vertebrate fauna ranged high-latitude austral Pangaea. The biogeography of the first dinosaurs is correlated with palaeolatitude-linked climatic barriers, and dinosaurian dispersal to the rest of the supercontinent was delayed until these barriers relaxed, suggesting that a climatic control with global influence on the initial composition of the terrestrial faunas that still persist today.

Funding

National Geographic Society, Award: NGS-157R-18

National Geographic Society, Award: CP-R004-17

National Science Foundation, Award: Graduate Research Fellowship Program

Fundação de Amparo à Pesquisa do Estado de São Paulo, Award: FAPESP 2020/07997-4