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Hypotheses & Objectives

We expect to identify and understand the relative role of individual stress factors by testing whether: (1) ecological structure and biodiversity of communities are significantly different after the extinction; (2) body size decrease is an early response to stress, with larger-sized species being more affected than smaller-sized taxa; (3) the ecological recovery follows a trajectory independent from that of ecological degradation.


Fossils are sampled quantitatively bed-by-bed in selected sections in Portugal and Spain. Shell length and height of specimens are measured, and data are analysed statistically with respect to body size and change in ecological composition. Faunal data are correlated with geochemical proxy data to identify the drivers of faunal change.

Preliminary results

A significant body size decrease before the extinction is observed, related to larger-sized brachiopods becoming both smaller and less abundant. Pre- and post-extinction assemblages differ both in taxonomic composition and ecological structure.


  • Luis V. Duarte (MARE & Universidade de Coimbra)
  • Tina Klein, Simone Kasemann and Friedrich Lucassen (MARUM & University of Bremen)
  • Simon Schneider (CASP)
  • Clemens V. Ullmann (University of Exeter)
  • Hans O. Pörtner, Charlotte Meyer and Sandra Goetze (Alfred Wegener Institute)
  • Wolfgang Kiessling (Friedrich-Alexander University Erlangen-Nuremberg)

Funding and Duration

  • DFG : 2016 - 2019
  • UNESCO and IUGS : 2017 - 2019