Diversidade de tetrápodes marinhos do Mesozoico e as extinções em massa

Mesozoic marine tetrapod diversity: mass extinctions and temporal heterogeneity in geological megabiases affecting vertebrates

Roger B. J. Benson1,*, Richard J. Butler2,*, Johan Lindgren3 and Adam S. Smith4

+ Author Affiliations

1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK

2Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, 80333 Munich, Germany

3GeoBiosphere Science Centre, Department of Geology, Lund University, 223 62 Lund, Sweden

4Natural History Division, National Museum of Ireland, Merrion Street, Dublin 2, Ireland

* Authors for correspondence (rbb27@cam.ac.uk, butler.richard.j@gmail.com).

Abstract

The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic–Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent ‘Lagerstätten effects’. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous–Palaeogene extinction.

palaeodiversity Mesozoic biodiversity rock record bias mass extinction marine reptiles

Footnotes

Received October 9, 2009.
Accepted October 26, 2009.
© 2009 The Royal Society

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Requer assinatura do Proceedings of the Royal Society B