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

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The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes). / Bright, Jen; Marugan-Lobon, Jesus; Rayfield, Emily; Cobb, Samuel.

In: BMC Evolutionary Biology, Vol. 19, No. 1, 104, 17.05.2019.

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Bright, Jen ; Marugan-Lobon, Jesus ; Rayfield, Emily ; Cobb, Samuel. / The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes). In: BMC Evolutionary Biology. 2019 ; Vol. 19, No. 1.

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@article{415ac43a20134d7c9050e7c52219f7f7,
title = "The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes)",
abstract = "Background: The 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. Results: Contrary 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). Conclusions: Our 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.",
keywords = "Allometry, Birds, Feeding, Geometric morphometrics, Integration, Parrots",
author = "Jen Bright and Jesus Marugan-Lobon and Emily Rayfield and Samuel Cobb",
year = "2019",
month = "5",
day = "17",
doi = "10.1186/s12862-019-1432-1",
language = "English",
volume = "19",
journal = "BMC Evolutionary Biology",
issn = "1471-2148",
publisher = "BioMed Central",
number = "1",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes)

AU - Bright, Jen

AU - Marugan-Lobon, Jesus

AU - Rayfield, Emily

AU - Cobb, Samuel

PY - 2019/5/17

Y1 - 2019/5/17

N2 - Background: The 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. Results: Contrary 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). Conclusions: Our 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.

AB - Background: The 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. Results: Contrary 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). Conclusions: Our 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.

KW - Allometry

KW - Birds

KW - Feeding

KW - Geometric morphometrics

KW - Integration

KW - Parrots

UR - http://www.scopus.com/inward/record.url?scp=85066011445&partnerID=8YFLogxK

U2 - 10.1186/s12862-019-1432-1

DO - 10.1186/s12862-019-1432-1

M3 - Article

VL - 19

JO - BMC Evolutionary Biology

JF - BMC Evolutionary Biology

SN - 1471-2148

IS - 1

M1 - 104

ER -