The shadow of forgotten ancestors differently constrains the fate of Alligatoroidea and Crocodyloidea

摘要: Aim We tested the hypothesis that evolutionary fates of two sister groups (Alligatoroidea and Crocodyloidea) are differently constrained by phylogenetic ecological (functional) factors in face climatic change. Location Global. Methods quantified disparity skull rostrum shape means geometric morphometrics. Mechanical performance was analyzed applying beam theory calculations to morphological data experimentally measured bite force. The phylogeny expressed form principal coordinates, first ones which were used as a set explanatory variables. Extents species occurrence computed using distribution maps. Finally, maximum size considered proxy body size. performed variation partitioning analyses order compare differential contributions Alligatoroidea Crocodyloidea. Results show higher ‘pure’ historical components than Crocodyloidea explaining both extent (after controlling for size). On contrary, rostra unequivocally shows functional component (linked on prey capture) phylogenetically structured environmental those found Alligatoroidea. obtained mass consistent with these patterns. In Alligatoroidea, contains signal Main Conclusions Our results suggest may react when faced significant changes. predict global changes will have more important effect (1) promoting trait shift, adaptation new diet speciation (2) modifying geographical range (which track favourable conditions).