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

VALDECANTOS SOLEDAD ; LOBO FERNANDO; PEROTTI M. GABRIELA; MORENO AZÓCAR DÉBORA L.; CRUZ FÉLIX B.

ZOOLOGISCHER ANZEIGER

ELSEVIER GMBH

Año: 2019 vol. 279 p. 152 - 163

0044-5231

In living organisms with sexual reproduction, the presence ofsexual size dimorphism (SSD) is common. The main explanations for thisphenomenon are based on sexual selection or the fecundity advantagehypothesis (natural selection). Here, we tested Rensch´s rule in speciesof the viviparous lizard genus Phymaturus; additionally, we tested ifthere is a pattern of sexual size dimorphism or if it depends upon othermorphological traits. We found no evidence for Rensch´s rule in theselizards. After testing for multiple or single regime evolutionarymodels, we found that body size most likely evolved under multi-regimeOrnstein-Uhlenbeck evolutionary model; the same was observed for abdomenwidth in females, a fecundity advantage hypothesis trait. For specieswith female biased SSD there is a positive relationship between snoutventlength and width of the belly, supporting the fecundity advantagehypothesis. Additionally, the relationship between brood size and broodmass with body size and body mass (respectively) were positive givingstrength to the fecundity advantage hypothesis. Finally, our results showmales did not show a clear pattern in relation to the sexual selectionhypothesis, probably because sexual selection is a complex aspect thatinvolves behavior and color. On the other hand, female body size andreproductive output are related to mean seasonal air temperature and itscombination with mean annual air temperature in an evolutionary fashionframework, such as fecundity advantage hypothesis in these lizards.