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Carboniferous–Permian climate change constrained early land vertebrate radiations


The Carboniferous–Permian transition (CPT) was Earth’s last pre-Quaternary icehouse–greenhouse transition, recording major shifts in late Palaeozoic climate regimes and increased continental seasonality over approximately 40 Myr. Its parallels to Quaternary climate change have inspired recent investigations into the impacts of purported rainforest collapse on palaeotropical vertebrate diversity, but little is known about how the protracted spatial dynamics of this transition impacted the emergence of modern tetrapod lineages. Here, we apply ecological ordinance analyses on a dataset of 286 CPT fossil vertebrate localities binned across four physiographic regions forming a palaeoequatorial transect. Our results clarify the spatiotemporal expansion of land-living vertebrates, demonstrating that the reduction of tropical wetlands accommodated emerging dryland-adapted amniote faunas from a western Pangaean epicentre. We call this west–east lag the ‘Vaughn–Olson model’: CPT climatic transitions were regionally diachronous with delayed proliferation of amniote-dominated dryland assemblages in the east. By combining our ecological analyses with a phylogenetic approach, we demonstrate that this pattern also applies to some co-occurring total-group amphibians, suggesting that there was pervasive selection for such dryland adaptations across the crown tetrapod tree, in contrast with stem tetrapods and ‘fishes’.

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Fig. 1: Clustering structure of CPT metacommunities across the CPT.
Fig. 2: PCO1 values are highly conserved across CPT vertebrate phylogeny.
Fig. 3: Palaeogeographic shifts in PCO1 scores during the CPT.

Data availability

Detailed materials and methods, supplementary display items and source data are available in the Supplementary Information. Additional information, including ‘R’ scripts, may be obtained from the corresponding authors upon reasonable request.


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We thank K. Angielczyk, C. Sidor and S. Sumida for support and helpful discussions during the inception of this project. D. Berman and A. Henrici (Carnegie Museum) and R. Cifelli and J. Person (Sam Noble Oklahoma Museum of Natural History) permitted access to useful collections records. We also thank the Paleobiology Database community and its major data contributors: J. Alroy, A. K. Behrensmeyer, R. Butler and J. Müller. J. Calede, K. Hollis, J. Marcot, K. Middleton and D. Vilhena assisted with preliminary analyses. We also thank M. Barton, J. Benca, M.-E. Benson, A. Bormet, J. Calede, K. Hollis, R. Hook, R. Irmis, E. Leckey, S. Lucas, J. Marcot, W. May, B. Peecook, J. Peters, L. Powers, K. Sears, D. Smith, N. Tabor and C. Wellstead for additional discussions and suggestions for improving this study. Finally, we thank R. Butler and E. Dunne for thoughtful reviews. A.K.H. has been supported by the University of Southern California and US Bureau of Land Management’s National Conservation Lands grants programme (number L17AC00064).

Author information

Authors and Affiliations



J.D.P. and A.K.H. collected and analysed the data. A.R.M. assisted with the European records. J.D.P. rendered the graphical illustrations. J.D.P. and A.K.H. composed the figures. All authors contributed to writing the manuscript.

Corresponding authors

Correspondence to Jason D. Pardo or Adam K. Huttenlocker.

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The authors declare no competing interests.

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Supplementary information

Supplementary information

Supplemental text describing data collection and analysis, and relevant references. Supplementary Figure 1: Comparison of diversity estimates across the CPT. a, Stage-specific rarefaction curves. b, Estimated Chao diversity across the CPT. c, Scatterplot of time of first occurrence of families versus mean PCO1 value. d, Scatterplot of time of last occurrence of families versus mean PCO1 value, showing weak negative trend. Supplementary Figure 2: Tree topology used in the comparative phylogenetic analysis. Node numbers represent node identifiers listed in the data sheet ‘Node Minimum Constraints’. Supplementary Figure 3: Time-calibrated phylogeny assembled for comparative phylogenetic analysis. Node minimum divergence constraints are listed in the online Supplementary Dataset 1 (numbers represent node identifiers from Supplementary Figure 2 and listed in the data sheet ‘Node Minimum Constraints’)

Reporting Summary

Dataset 1

Source data for ecological ordinance analyses, including presence–absence matrix

Dataset 2

Composite tree used for phylogenetic analyses in NEXUS format

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Pardo, J.D., Small, B.J., Milner, A.R. et al. Carboniferous–Permian climate change constrained early land vertebrate radiations. Nat Ecol Evol 3, 200–206 (2019).

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