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The narrow active temperature ranges of ectothermic tetrapods can be used as proxies for reconstructing paleoclimates. Here we deduce the climatic preferences of major Permo-Triassic tetrapod groups based on their known geographic distributions, the critical thermal limits of living tetrapods, and paleoclimate information from other sources. The resulting preferred temperature sequence of amniotes places most Triassic archosauromorphs at the high end of the spectrum, with preferred temperatures over 32 ◦ C in some cases, followed by captorhinids, pareiasaurs, procolophonids, cynognathian cynodonts, dicynodonts (excluding Lystrosaurus), Proterosuchus fergusi, and finally Lystrosaurus at the lowest preferred temperature. The poleward distribution of Permian Lystrosaurus marks the border of cool temperate climates, whereas Triassic Lystrosaurus delineates the border of the arid zone. Most temnospondyls indicate the availability of perennial water sources. Captorhinids and pareiasaurs preferred dry climates, whereas dicynodonts preferred wetter conditions. Based on current evidence, central Pangea transitioned from an arid zone to a tropical zone during the late Olenekian.
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Tetrapod turnover during the Permo-Triassic transition explained by temperature change
Global temperatures significantly changed from the late Permian to the Early Triassic: the Earth transformed from a cool world to a hothouse climate. This transition undoubtedly had a strong impact on tetrapod physiology and distribution. During the global cooling, tetrapods generally increased their size; and the currently recognized late Permian tetrapod extinction, exemplified by the record preserved in the South African Karoo Basin, occurred in the late stage of cooling. Rapid warming in the Early Triassic is predicted to have resulted in extinctions and/or local extirpation of low latitude tetrapods, but the very limited fossil record from this region makes testing this hypothesis difficult. Warming is predicted to have had less negative impacts on the tetrapod diversity of mid-latitudes, and promoted the success of tetrapods in the high latitudes. Based on the known fossil record, a tetrapod gap could have existed in central Pangea between ~30◦ N and ~ 40◦S, and lasting from the Induan to the early Spathian. However, the exact boundaries of this gap likely varied over time, and it could have encompassed a larger area during the hottest phases (Griesbachian and near the Smithian–Spathain boundary).
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- Award ID(s):
- 1714829
- PAR ID:
- 10344309
- Date Published:
- Journal Name:
- Earthscience reviews
- Volume:
- 224
- ISSN:
- 0012-8252
- Page Range / eLocation ID:
- 103886
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/https://doi.org/10.1016/j.earscirev.2021.103886
