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Allometry of sexual size dimorphism in turtles: a comparison of mass and length data
BACKGROUND: The macroevolutionary pattern of Rensch’s Rule (positive allometry of sexual size dimorphism) has had mixed support in turtles. Using the largest carapace length dataset and only large-scale body mass dataset assembled for this group, we determine (a) whether turtles conform to Rensch’s...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
PeerJ Inc.
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5267567/ https://www.ncbi.nlm.nih.gov/pubmed/28149687 http://dx.doi.org/10.7717/peerj.2914 |
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author | Regis, Koy W. Meik, Jesse M. |
author_facet | Regis, Koy W. Meik, Jesse M. |
author_sort | Regis, Koy W. |
collection | PubMed |
description | BACKGROUND: The macroevolutionary pattern of Rensch’s Rule (positive allometry of sexual size dimorphism) has had mixed support in turtles. Using the largest carapace length dataset and only large-scale body mass dataset assembled for this group, we determine (a) whether turtles conform to Rensch’s Rule at the order, suborder, and family levels, and (b) whether inferences regarding allometry of sexual size dimorphism differ based on choice of body size metric used for analyses. METHODS: We compiled databases of mean body mass and carapace length for males and females for as many populations and species of turtles as possible. We then determined scaling relationships between males and females for average body mass and straight carapace length using traditional and phylogenetic comparative methods. We also used regression analyses to evalutate sex-specific differences in the variance explained by carapace length on body mass. RESULTS: Using traditional (non-phylogenetic) analyses, body mass supports Rensch’s Rule, whereas straight carapace length supports isometry. Using phylogenetic independent contrasts, both body mass and straight carapace length support Rensch’s Rule with strong congruence between metrics. At the family level, support for Rensch’s Rule is more frequent when mass is used and in phylogenetic comparative analyses. Turtles do not differ in slopes of sex-specific mass-to-length regressions and more variance in body size within each sex is explained by mass than by carapace length. DISCUSSION: Turtles display Rensch’s Rule overall and within families of Cryptodires, but not within Pleurodire families. Mass and length are strongly congruent with respect to Rensch’s Rule across turtles, and discrepancies are observed mostly at the family level (the level where Rensch’s Rule is most often evaluated). At macroevolutionary scales, the purported advantages of length measurements over weight are not supported in turtles. |
format | Online Article Text |
id | pubmed-5267567 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | PeerJ Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-52675672017-02-01 Allometry of sexual size dimorphism in turtles: a comparison of mass and length data Regis, Koy W. Meik, Jesse M. PeerJ Ecology BACKGROUND: The macroevolutionary pattern of Rensch’s Rule (positive allometry of sexual size dimorphism) has had mixed support in turtles. Using the largest carapace length dataset and only large-scale body mass dataset assembled for this group, we determine (a) whether turtles conform to Rensch’s Rule at the order, suborder, and family levels, and (b) whether inferences regarding allometry of sexual size dimorphism differ based on choice of body size metric used for analyses. METHODS: We compiled databases of mean body mass and carapace length for males and females for as many populations and species of turtles as possible. We then determined scaling relationships between males and females for average body mass and straight carapace length using traditional and phylogenetic comparative methods. We also used regression analyses to evalutate sex-specific differences in the variance explained by carapace length on body mass. RESULTS: Using traditional (non-phylogenetic) analyses, body mass supports Rensch’s Rule, whereas straight carapace length supports isometry. Using phylogenetic independent contrasts, both body mass and straight carapace length support Rensch’s Rule with strong congruence between metrics. At the family level, support for Rensch’s Rule is more frequent when mass is used and in phylogenetic comparative analyses. Turtles do not differ in slopes of sex-specific mass-to-length regressions and more variance in body size within each sex is explained by mass than by carapace length. DISCUSSION: Turtles display Rensch’s Rule overall and within families of Cryptodires, but not within Pleurodire families. Mass and length are strongly congruent with respect to Rensch’s Rule across turtles, and discrepancies are observed mostly at the family level (the level where Rensch’s Rule is most often evaluated). At macroevolutionary scales, the purported advantages of length measurements over weight are not supported in turtles. PeerJ Inc. 2017-01-24 /pmc/articles/PMC5267567/ /pubmed/28149687 http://dx.doi.org/10.7717/peerj.2914 Text en ©2017 Regis and Meik 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 use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. |
spellingShingle | Ecology Regis, Koy W. Meik, Jesse M. Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title | Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title_full | Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title_fullStr | Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title_full_unstemmed | Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title_short | Allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
title_sort | allometry of sexual size dimorphism in turtles: a comparison of mass and length data |
topic | Ecology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5267567/ https://www.ncbi.nlm.nih.gov/pubmed/28149687 http://dx.doi.org/10.7717/peerj.2914 |
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