Global Taxonomic Diversity of Anomodonts (Tetrapoda, Therapsida) and the Terrestrial Rock Record Across the Permian-Triassic Boundary
2008

Diversity Patterns of Anomodonts Across the Permian-Triassic Boundary

Sample size: 128 publication Evidence: moderate

Author Information

Author(s): Fröbisch Jörg

Primary Institution: Department of Biology, University of Toronto, Mississauga, Ontario, Canada

Hypothesis

This study investigates the diversity patterns of Anomodontia, an extinct group of therapsid synapsids, particularly across the end-Permian extinction event.

Conclusion

Anomodonts experienced three distinct phases of diversification interrupted by extinctions, with the end-Permian extinction being the most severe.

Supporting Evidence

  • Anomodonts were the dominant terrestrial tetrapods during the Permian.
  • The end-Permian extinction event led to a significant decline in anomodont diversity.
  • Taxonomic diversity analysis revealed three distinct phases of diversification for anomodonts.
  • Normalized diversity curves indicated a continuous decline in anomodont richness from the Middle Permian to the Late Triassic.
  • Extinction rates varied among different clades, affecting anomodont survival.
  • Rock record bias was shown to influence observed diversity patterns.
  • Anomodont diversity was assessed using a global perspective to minimize local extinction influences.

Takeaway

This study looks at how a group of ancient animals called anomodonts changed in number over time, especially during a big extinction event.

Methodology

The study utilized quantitative methods to assess taxonomic diversity at the genus and species level across various time intervals.

Potential Biases

There is a risk of rock record bias affecting diversity assessments due to the correlation between the number of taxa and the number of formations.

Limitations

The stratigraphic ranges of anomodont taxa are not precisely known, and there is potential taxonomic bias towards Permian taxa.

Statistical Information

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0003733

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