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Article: Brachiopod shell thickness links environment and evolution

Palaeontology - Vol. 63 Part 1 - Cover Image
Publication: Palaeontology
Volume: 63
Part: 1
Publication Date: January 2020
Page(s): 171 183
Author(s): Uwe Balthasar, Jisuo Jin, Linda Hints, and Maggie Cusack
Addition Information

How to Cite

BALTHASAR, U., JIN, J., HINTS, L., CUSACK, M. 2020. . Palaeontology, 63, 1, 171-183. DOI: /doi/10.1111/pala.12450

Author Information

  • Uwe Balthasar - School of Geography, Earth and Environmental Science University of Plymouth PL4 8AA Plymouth UK
  • Jisuo Jin - Department of Earth Sciences Western University London ON N6A 5B7 Canada
  • Linda Hints - Institute of Geology Tallinn University of Technology Ehitajate tee 5 19086 Tallinn Estonia
  • Maggie Cusack - Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK

Publication History

  • Issue published online: 24 December 2019
  • Manuscript Accepted: 28 June 2019
  • Manuscript Received: 23 November 2018

Funded By

Palaeontological Association

Online Version Hosted By

Wiley Online Library
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While it is well established that the shapes and sizes of shells are strongly phylogenetically controlled, little is known about the phylogenetic constraints on shell thickness. Yet, shell thickness is likely to be sensitive to environmental fluctuations and has the potential to illuminate environmental perturbations through deep time. Here we systematically quantify the thickness of the anterior brachiopod shell which protects the filtration chamber and is thus considered functionally homologous across higher taxa of brachiopods. Our data come from 66 genera and 10 different orders and shows well‐defined upper and lower boundaries of anterior shell thickness. For Ordovician and Silurian brachiopods we find significant order‐level differences and a trend of increasing shell thickness with water depth. Modern (Cenozoic) brachiopods, by comparison, fall into the lower half of observed shell thicknesses. Among Ordovician–Silurian brachiopods, older stocks commonly have thicker shells, and thick‐shelled taxa contributed more prominently to the Great Ordovician Biodiversification but suffered more severely during the Late Ordovician Mass Extinction. Our data highlight a significant reduction in maximum and minimum shell thickness following the Late Ordovician mass extinction. This points towards stronger selection pressure for energy‐efficient shell secretion during times of crisis.

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