Chromatic variability and sexual dimorphism in the rocky lizard Phymaturus verdugo

CORBALAN VALERIA; VICENZI NADIA; MORENO AZÓCAR, DÉBORA LINA; LITERAS SOFÍA

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2018

0008-4301

The genus Phymaturus comprises lizards inhabiting cold environments in high altitudes or latitudes. Phymaturus verdugo is a species characterised by cephalic melanism, which is interpreted as a character associated with sexual dimorphism, present only in males. Using spectrophotometry and photography, we demonstrated this species shows a high chromatic variability, and melanism is also present in females. By comparing variables of colour in 15 patches of the body we found significant differences between sexes in all patches, indicating a strong sexual dichromatism that involves the entire body, not only the cephalic region. Body temperature had no effect on skin reflectance or melanism indicating that thermoregulation in the first hours of the day is not mediated by colour changes. Contrary to our predictions, we found no evidence of better body condition in darker individuals. Our study has broken some paradigms regarding the genus Phymaturus, and suggests that our human perception of colour as well as to work with small samples can lead to misidentification or erroneous descriptions of species. We consider that heating rates, and other functions of melanism like crypsis, sexual selection, immune response or UV protection should be explored in the future to understand the existence of chromatic variability in this genus.