Phenotypic plasticity, sexual dimorphism and Rensch's rule in turtles

Analysis of the Sexual Variability in the Shell of the Spanish Upper Cretaceous Turtle Dortoka Vasconica (Pan-Pleurodira, Dortokidae)

“…Likewise, both dimorphs coincide with those observed in extant and extinct panpleurodiran turtles. Specifically, in the formers, the variation of the xiphiplastral area is identified in a great number of taxa as sexually dimorphic (Host, 2006;Pritchard, 2008;Ceballos-Fonseca, 2010). However, in the literature, the direction as well as the magnitude of the sexual dimorphism have been recognized as variable at genus level in extant pleurodiran turtles, without following a clear phylogenetic pattern.…”

“…Likewise, several extant pleurodiran clades that are part of the current biodiversity have been included in order to increase the comparative framework and evaluate, in a preliminary way, how sexual dimorphism has been manifested throughout the evolutionary history of this lineage of turtles. The comparisons with these extant species were also carried out through the direct observation of some of them (see S3 of the Supplementary Information) and the information provided in previous studies (Pritchard, 1979;Bour, 1983;Ernst, 1986;Kuchling, 1988;Strydom, 2001;Iverson & Vogt, 2002;Trembath & Freier, 2004;García, 2005;Host, 2006;Gerlach, 2008;Broadley & Boycott, 2009;Pritchard, 2008;Böhm, 2010;Ceballos-Fonseca, 2010;González-Zárate, 2014;Páez et al, 2012Páez et al, , 2013Gallego-García & Forero-Medina, 2014;Bour et al, 2016;Sepúlveda-Seguro et al, 2020). A quantitative approach was performed for both D. vasconica and several extant forms.…”

The shell measurements that best describe sexual dimorphism in the spur-thighed tortoise <em>Testudo graeca</em> from Algeria

“…Phenotypic plasticity makes chelonians particularly prone to the morphological studies that explore the interactions of selection, life history traits and local conditions (Fritz et al, 2007;Ceballos-Fonseca, 2010). On tortoises of the genus Testudo (with a broad southwestern Palearctic distribution), morphometric studies have assessed morphological divergence between and within subspecies (Carretero et al, 2005), have explored Bergmann's or Rensch's rules (Sacchi et al, 2007;Werner et al, 2016), compared sexual size and shape dimorphism (SSD and SShD, respectively; e.g.…”