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Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms

Body size and body-size shifts broadly impact life-history parameters of all animals, which has made accurate body-size estimates for extinct taxa an important component of understanding their paleobiology. Among extinct crocodylians and their precursors (e.g., suchians), several methods have been d...

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Autores principales: O’Brien, Haley D, Lynch, Leigha M, Vliet, Kent A, Brueggen, John, Erickson, Gregory M, Gignac, Paul M
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7671145/
https://www.ncbi.nlm.nih.gov/pubmed/33791523
http://dx.doi.org/10.1093/iob/obz006
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author O’Brien, Haley D
Lynch, Leigha M
Vliet, Kent A
Brueggen, John
Erickson, Gregory M
Gignac, Paul M
author_facet O’Brien, Haley D
Lynch, Leigha M
Vliet, Kent A
Brueggen, John
Erickson, Gregory M
Gignac, Paul M
author_sort O’Brien, Haley D
collection PubMed
description Body size and body-size shifts broadly impact life-history parameters of all animals, which has made accurate body-size estimates for extinct taxa an important component of understanding their paleobiology. Among extinct crocodylians and their precursors (e.g., suchians), several methods have been developed to predict body size from suites of hard-tissue proxies. Nevertheless, many have limited applications due to the disparity of some major suchian groups and biases in the fossil record. Here, we test the utility of head width (HW) as a broadly applicable body-size estimator in living and fossil suchians. We use a dataset of sexually mature male and female individuals (n = 76) from a comprehensive sample of extant suchian species encompassing nearly all known taxa (n = 22) to develop a Bayesian phylogenetic model for predicting three conventional metrics for size: body mass, snout–vent length, and total length. We then use the model to estimate size parameters for a select series of extinct suchians with known phylogenetic affinity (Montsechosuchus, Diplocynodon, and Sarcosuchus). We then compare our results to sizes reported in the literature to exemplify the utility of our approach for a broad array of fossil suchians. Our results show that HW is highly correlated with all other metrics (all R(2)≥0.85) and is commensurate with femoral dimensions for its reliably as a body-size predictor. We provide the R code in order to enable other researchers to employ the model in their own research.
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spelling pubmed-76711452021-03-30 Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms O’Brien, Haley D Lynch, Leigha M Vliet, Kent A Brueggen, John Erickson, Gregory M Gignac, Paul M Integr Org Biol Research Article Body size and body-size shifts broadly impact life-history parameters of all animals, which has made accurate body-size estimates for extinct taxa an important component of understanding their paleobiology. Among extinct crocodylians and their precursors (e.g., suchians), several methods have been developed to predict body size from suites of hard-tissue proxies. Nevertheless, many have limited applications due to the disparity of some major suchian groups and biases in the fossil record. Here, we test the utility of head width (HW) as a broadly applicable body-size estimator in living and fossil suchians. We use a dataset of sexually mature male and female individuals (n = 76) from a comprehensive sample of extant suchian species encompassing nearly all known taxa (n = 22) to develop a Bayesian phylogenetic model for predicting three conventional metrics for size: body mass, snout–vent length, and total length. We then use the model to estimate size parameters for a select series of extinct suchians with known phylogenetic affinity (Montsechosuchus, Diplocynodon, and Sarcosuchus). We then compare our results to sizes reported in the literature to exemplify the utility of our approach for a broad array of fossil suchians. Our results show that HW is highly correlated with all other metrics (all R(2)≥0.85) and is commensurate with femoral dimensions for its reliably as a body-size predictor. We provide the R code in order to enable other researchers to employ the model in their own research. Oxford University Press 2019-03-23 /pmc/articles/PMC7671145/ /pubmed/33791523 http://dx.doi.org/10.1093/iob/obz006 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
O’Brien, Haley D
Lynch, Leigha M
Vliet, Kent A
Brueggen, John
Erickson, Gregory M
Gignac, Paul M
Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title_full Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title_fullStr Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title_full_unstemmed Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title_short Crocodylian Head Width Allometry and Phylogenetic Prediction of Body Size in Extinct Crocodyliforms
title_sort crocodylian head width allometry and phylogenetic prediction of body size in extinct crocodyliforms
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7671145/
https://www.ncbi.nlm.nih.gov/pubmed/33791523
http://dx.doi.org/10.1093/iob/obz006
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