The contribution of functional traits to the understanding of palaeoenvironmental changes

Résumé En

Performance traits involved in feeding are relevant ecological indicators as they respond to variation in the environment. However, their use for paleoenvironmental inferences is limited in the literature. In this study, we evaluated the relevance of estimated bite force in reconstructing the paleoecology of shrews. We explored the relationships between mandible morphology, bite force estimates, and the ecological context. Through a geometric morphometric approach, we quantified mandible shape diversity in shrews of the archaeological site El Harhoura 2 (Rabat, Morocco), dated from the Late Pleistocene to the Holocene. Morphological groups were used instead of taxa as phenotypic units to explore how morphological and performance traits are related to variation in the environment through time. Results showed that morphological groups acted as phenotypic response units to environmental change. Estimated bite force was related to paleoenvironmental variation over the considered period, with a particular sensitivity to arid/humid transitions. The complementarity of morphological and performance indicators allowed us to infer functional convergence and divergence among shrews. Our results suggest that performance traits may be relevant indicators of changes in paleoenvironments. This approach opens up new possibilities for exploring the impact of environmental changes in extinct organisms.