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The latitudinal diversity gradient of tetrapods across the Permo-Triassic mass extinction and recovery interval - PubMed

  • ️Wed Jan 01 2020

The latitudinal diversity gradient of tetrapods across the Permo-Triassic mass extinction and recovery interval

Bethany J Allen et al. Proc Biol Sci. 2020.

Abstract

The decline in species richness from the equator to the poles is referred to as the latitudinal diversity gradient (LDG). Higher equatorial diversity has been recognized for over 200 years, but the consistency of this pattern in deep time remains uncertain. Examination of spatial biodiversity patterns in the past across different global climate regimes and continental configurations can reveal how LDGs have varied over Earth history and potentially differentiate between suggested causal mechanisms. The Late Permian-Middle Triassic represents an ideal time interval for study, because it is characterized by large-scale volcanic episodes, extreme greenhouse temperatures and the most severe mass extinction event in Earth history. We examined terrestrial and marine tetrapod spatial biodiversity patterns using a database of global tetrapod occurrences. Terrestrial tetrapods exhibit a bimodal richness distribution throughout the Late Permian-Middle Triassic, with peaks in the northern low latitudes and southern mid-latitudes around 20-40° N and 60° S, respectively. Marine reptile fossils are known almost exclusively from the Northern Hemisphere in the Early and Middle Triassic, with highest diversity around 20° N. Reconstructed terrestrial LDGs contrast strongly with the generally unimodal gradients of today, potentially reflecting high global temperatures and prevailing Pangaean super-monsoonal climate system during the Permo-Triassic.

Keywords: Tetrapoda; biodiversity; climate change; greenhouse; mass extinction; sampling bias.

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Conflict of interest statement

We have no competing interests to declare.

Figures

Figure 1.
Figure 1.

Tetrapod diversity by latitude in the Late Permian, Early Triassic and Middle Triassic. The grey bars indicate 30–60° N and S. (a) Palaeo-rotated occurrence locations plotted over maps from Scotese [59]; maps represent the Lopingian, Induan-Olenekian and Ladinian. (b) Raw occurrences within 20° latitude bins (e.g. central bin is 10° N–10° S). (c) Squares diversity by latitudinal bin for terrestrial (green) and marine (blue) tetrapods. (d,e) Interpolated diversity by latitudinal bin for terrestrial tetrapods (d) and marine tetrapods (e). Bins with less than three species have been plotted as ‘0’, while missing points indicate an estimated diversity of more than three times the observed value. Error bars indicate 95% confidence intervals. The oldest marine tetrapod fossils are Olenekian (late Early Triassic; 251–247 Ma) in age.

Figure 2.
Figure 2.

Smoothed latitudinal gradients for species of modern birds (a), mammals (b) and amphibians (c), compared with Early Triassic terrestrial tetrapods (as an example) based on interpolation analyses (d). Modern gradients derive from data obtained from BiodiversityMapping.org. Silhouettes are from Phylopic.org. (Online version in colour.)

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References

    1. von Humboldt A, Bonpland A. 2009. [1807] Essay on the geography of plants. In Romanowski S, translator. Essay on the geography of plants (ed. Jackson ST.), pp. 49–144. Chicago, IL: University of Chicago Press.
    1. Gaston KJ. 2000. Global patterns in biodiversity. Nature 405, 220–227. (10.1038/35012228) - DOI - PubMed
    1. Willig MR, Kaufman DM, Stevens RD. 2003. Latitudinal gradients of biodiversity: pattern, process, scale and synthesis. Annu. Rev. Ecol. Evol. Syst. 34, 273–309. (10.1146/annurev.ecolsys.34.012103.144032) - DOI
    1. Hillebrand H. 2004. On the generality of the latitudinal diversity gradient. Am. Nat. 163, 192–211. (10.1086/381004) - DOI - PubMed
    1. Mannion PD, Upchurch P, Benson RBJ, Goswami A. 2014. The latitudinal diversity gradient through deep time. TREE 29, 42–50. (10.1016/j.tree.2013.09.012) - DOI - PubMed

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