Sexual size dimorphism, allometry and fecundity in a lineage of South American viviparous lizards (Liolaemidae: Phymaturus)

Publication date: Available online 21 February 2019Source: Zoologischer AnzeigerAuthor(s): Soledad Valdecantos, Fernando Lobo, M. Gabriela Perotti, Débora L. Moreno Azócar, Félix B. CruzAbstractIn living organisms with sexual reproduction, the presence of sexual size dimorphism (SSD) is common. The main explanations for this phenomenon are based on sexual selection or the fecundity advantage hypothesis (natural selection). Here, we tested Rensch’s rule in species of the viviparous lizard genus Phymaturus; additionally, we tested if there is a pattern of sexual size dimorphism or if it depends upon other morphological traits. We found no evidence for Rensch’s rule in these lizards. After testing for multiple or single regime evolutionary models, we found that body size most likely evolved under multi-regime Ornstein-Uhlenbeck evolutionary model; the same was observed for abdomen width in females, a fecundity advantage hypothesis trait. For species with female biased SSD there is a positive relationship between snout-vent length and width of the belly, supporting the fecundity advantage hypothesis. Additionally, the relationship between brood size and brood mass with body size and body mass (respectively) were positive giving strength to the fecundity advantage hypothesis. Finally, our results show males did not show a clear pattern in relation to the sexual selection hypothesis, probably because sexual selection is a complex aspect that involves behavior and color. On t...
Source: A Journal of Comparative Zoology - Category: Zoology Source Type: research