摘要
We explored the morphological organization of the skull within Crocodylidae,analyzing functional and phylogenetic interactions between its 2 constituent functional modules:the rostrum and the postrostrum.We used geometric morphometrics to identify localized shape changes,focusing on the differences between the major clades of the crown-group Crocodylia:Alligatoridae and Crocodylidae.We used published bite performance data to correlate rostral function with postrostral morphology.The skull modules appear more integrated within Alligatoridae than within Crocodyliade.Phylogenetic effects on shape variation are more evident in Alligatoridae than in Crocodylidae,where functional parameters concerning the rostral morphology are proportionally more important than phylogeny.Long-snouted species are characterized by low structural performance,which is significantly associated with a reduction of the pterygoid-quadrate cranial nipper,suggesting that the nipper is important for the ingestion of large food items in generalist species.This functional association is coupled with a significant evolutionary allometry at the clade level,while Alligatoridae and Crocodylidae show different degrees of evolutionary allometry for their entire shape and rostrum.The postrostrum is more conservative than the rostrum in terms of morphospace occupation,evolutionary allometry and phylogenetic signal.
基金
Paolo Piras had access to the collections of the Natural History Museum in London,the Institut Royal des Sciences Naturelles in Bruxelles and the Museum d’Histoire Naturelle in Paris thanks to the SYNTHESYS program,and to the collection of the Field Museum in Chicago thanks to the Visiting Scholarship Program.Funds from the Geological Science Department of‘Roma Tre’University made possible the visit to the American Museum of Natural History,New York.Part of this research was conducted during a postdoctoral visit by Paolo Piras,supervised by Jorge Cubo,to the UniversitéPierre et Marie Curie.Funds were also provided by Project CGL-2009-11838 from the Spanish Ministerio de Ciencia e Innovacion Cientifica,Spain.
