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Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull

All modern crocodyliforms (alligators, crocodiles and the gharial) are semi-aquatic generalist carnivores that are relatively similar in cranial form and function. However, this homogeneity represents just a fraction of the variation that once existed in the clade, which includes extinct herbivorous...

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Autores principales: Felice, Ryan N., Pol, Diego, Goswami, Anjali
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8277476/
https://www.ncbi.nlm.nih.gov/pubmed/34256005
http://dx.doi.org/10.1098/rspb.2021.0919
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author Felice, Ryan N.
Pol, Diego
Goswami, Anjali
author_facet Felice, Ryan N.
Pol, Diego
Goswami, Anjali
author_sort Felice, Ryan N.
collection PubMed
description All modern crocodyliforms (alligators, crocodiles and the gharial) are semi-aquatic generalist carnivores that are relatively similar in cranial form and function. However, this homogeneity represents just a fraction of the variation that once existed in the clade, which includes extinct herbivorous and marine forms with divergent skull structure and function. Here, we use high-dimensional three-dimensional geometric morphometrics to quantify whole-skull morphology across modern and fossil crocodyliforms to untangle the factors that shaped the macroevolutionary history and relatively low phenotypic variation of this clade through time. Evolutionary modelling demonstrates that the pace of crocodyliform cranial evolution is initially high, particularly in the extinct Notosuchia, but slows near the base of Neosuchia, with a late burst of rapid evolution in crown-group crocodiles. Surprisingly, modern crocodiles, especially Australian, southeast Asian, Indo-Pacific species, have high rates of evolution, despite exhibiting low variation. Thus, extant lineages are not in evolutionary stasis but rather have rapidly fluctuated within a limited region of morphospace, resulting in significant convergence. The structures related to jaw closing and bite force production (e.g. pterygoid flange and quadrate) are highly variable, reinforcing the importance of function in driving phenotypic variation. Together, these findings illustrate that the apparent conservativeness of crocodyliform skulls betrays unappreciated complexity in their macroevolutionary dynamics.
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spelling pubmed-82774762021-07-21 Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull Felice, Ryan N. Pol, Diego Goswami, Anjali Proc Biol Sci Palaeobiology All modern crocodyliforms (alligators, crocodiles and the gharial) are semi-aquatic generalist carnivores that are relatively similar in cranial form and function. However, this homogeneity represents just a fraction of the variation that once existed in the clade, which includes extinct herbivorous and marine forms with divergent skull structure and function. Here, we use high-dimensional three-dimensional geometric morphometrics to quantify whole-skull morphology across modern and fossil crocodyliforms to untangle the factors that shaped the macroevolutionary history and relatively low phenotypic variation of this clade through time. Evolutionary modelling demonstrates that the pace of crocodyliform cranial evolution is initially high, particularly in the extinct Notosuchia, but slows near the base of Neosuchia, with a late burst of rapid evolution in crown-group crocodiles. Surprisingly, modern crocodiles, especially Australian, southeast Asian, Indo-Pacific species, have high rates of evolution, despite exhibiting low variation. Thus, extant lineages are not in evolutionary stasis but rather have rapidly fluctuated within a limited region of morphospace, resulting in significant convergence. The structures related to jaw closing and bite force production (e.g. pterygoid flange and quadrate) are highly variable, reinforcing the importance of function in driving phenotypic variation. Together, these findings illustrate that the apparent conservativeness of crocodyliform skulls betrays unappreciated complexity in their macroevolutionary dynamics. The Royal Society 2021-07-14 2021-07-14 /pmc/articles/PMC8277476/ /pubmed/34256005 http://dx.doi.org/10.1098/rspb.2021.0919 Text en © 2021 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Palaeobiology
Felice, Ryan N.
Pol, Diego
Goswami, Anjali
Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title_full Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title_fullStr Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title_full_unstemmed Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title_short Complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
title_sort complex macroevolutionary dynamics underly the evolution of the crocodyliform skull
topic Palaeobiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8277476/
https://www.ncbi.nlm.nih.gov/pubmed/34256005
http://dx.doi.org/10.1098/rspb.2021.0919
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