The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes)

BMC Evolutionary Biology

Jen A. Bright¹  Emily J. Rayfield²  Samuel N. Cobb³  Jesús Marugán-Lobón⁴ 

[1] 0000 0001 2353 285X, grid.170693.a, School of Geosciences, University of South Florida, 33620, Tampa, FL, USA;0000 0004 1936 7603, grid.5337.2, School of Earth Sciences, University of Bristol, BS8 1TQ, Bristol, UK;0000 0004 1936 9668, grid.5685.e, Department of Archaeology, University of York, YO10 5DD, York, UK;0000 0004 1936 9668, grid.5685.e, Hull York Medical School, University of York, YO10 5DD, York, UK;0000000119578126, grid.5515.4, Unidad de Paleontologıa, Departamento Biologıa, Universidad Autonoma de Madrid, Cantoblanco, 28049, Madrid, Spain;Dinosaur Institute, Natural History Musuem of Los Angeles County, 90007, Los Angeles, CA, USA;

关键词: Birds;    Geometric morphometrics;    Allometry;    Integration;    Feeding;    Parrots;   

DOI  :  10.1186/s12862-019-1432-1

来源: publisher

【 摘 要 】

BackgroundThe Psittaciformes (parrots and cockatoos) are characterised by their large beaks, and are renowned for their ability to produce high bite forces. These birds also possess a suite of modifications to their cranial architecture interpreted to be adaptations for feeding on mechanically resistant foods, yet the relationship between cranial morphology and diet has never been explicitly tested. Here, we provide a three-dimensional geometric morphometric analysis of the developmental and biomechanical factors that may be influencing the evolution of psittaciformes’ distinctive cranial morphologies.ResultsContrary to our own predictions, we find that dietary preferences for more- or less- mechanically resistant foods have very little influence on beak and skull shape, and that diet predicts only 2.4% of the shape variation in psittaciform beaks and skulls. Conversely, evolutionary allometry and integration together predict almost half the observed shape variation, with phylogeny remaining an important factor in shape identity throughout our analyses, particularly in separating cockatoos (Cacatuoidea) from the true parrots (Psittacoidea).ConclusionsOur results are similar to recent findings about the evolutionary trajectories of skull and beak shape in other avian families. We therefore propose that allometry and integration are important factors causing canalization of the avian head, and while diet clearly has an influence on beak shape between families, this may not be as important at driving evolvability within families as is commonly assumed.

【 授权许可】

CC BY