Phylogenetic signal and variation of visceral pigmentation in eight anuran families

Abstract

Provete, D. B, Franco‐Belussi, L., de Souza Santos, L. R., Zieri, R., Moresco, R. M., Martins, I. A., de Almeida, S. C., & de Oliveira, C. (2012). Phylogenetic signal and variation of visceral pigmentation in eight anuran families. —Zoologica Scripta, 41, 547‐556.Visceral pigmentation is found in several organs and structures of ectothermic animals, comprising the extracutaneous pigmentary system. Its function is not well defined, although it is known that melanin is produced and stored inside pigmented cells. Previous studies demonstrated that the distribution of visceral pigmentation is neither homogeneous among organs among anuran species. We described the diversity of visceral pigmentation in 12 organs/structures from 32 anuran species belonging to eight families in a phylogenetic context. We also determined in which node(s) of the phylogeny there is more variation in the pigmentation and whether this variation has phylogenetic signal. The visceral pigment cells in organs and structures of the abdominal cavity varied among genera. All species had pigmentation in the urogenital and cardiorespiratory systems, whereas the stomach lacks pigmentation in all species. We also found a phylogenetic signal for pigmentation in all organs and structures taken together, besides heart, testes, lumbar parietal peritoneum and lumbar nerve plexus when considered separately. Overall, considering all organs, the highest diversity of categories of pigmentation was found in the nodes corresponding to Cruciabatrachia and Athesphatanura. This study constitutes the first step towards understanding the evolution of visceral pigmentation in anurans.

Environmental correlates of internal coloration in frogs vary throughout space and lineages

“…We found that the amount of melanin on a given organ is determined jointly by its physiology, environmental variables, and phylogenetic relationship (see also Provete et al, 2012). Melanocytes have distinct physiology depending on the external coloration of the animal.…”

“…Here, we expand our previous study (Provete et al, 2012) to address this question using multivariate methods (Pavoine et al, 2011) considering intraspecific variation in organ coloration. Specifically, we asked how environmental variables (temperature, UV, and photoperiod) influence the internal coloration of anuran species after controlling for spatial and phylogenetic autocorrelations.…”

“…The main goal of these experimental studies was to demonstrate the mechanistic basis of the responses of pigmentary cells to these factors. The only large-scale study that evaluated the distribution of coloration categories on organs of 32 Neotropical anuran species (Provete et al, 2012) found that the intensity of coloration in several organs has a phylogenetic component. Nonetheless, little is known about how the organ’s coloration of anuran species vary in response to environmental factors over broad spatial scales.…”

Environmental correlates of internal coloration in frogs vary throughout space and lineages

“…The main goal of these studies was to demonstrate the mechanistic basis of the responses of pigmentary cells to climatic factors. Additionally, a large‐scale study using 32 Neotropical anuran species found that closely related species have similar degrees of coloration on the heart, testes, lumbar parietal peritoneum, and lumbar nerve plexus (Provete et al., ). These authors also found that some families, such as Hylidae, Leptodactylidae, and Hylodidae, have more variation in the amount of coloration.…”

“…Here, we build upon our previous study (Provete et al., ) to test which climatic variables (temperature, UV, and photoperiod) have the highest covariation with coloration on the surface of internal organs in anurans using a three‐table ordination method called RLQ (R‐mode Linked to Q‐mode; Dolédec, Chessel, ter Braak, & Champely, ; Pavoine, Vela, Gachet, Belair, & Bonsall, ). Internal melanin can possibly confer adaptive advantages for species in response to environmental variables.…”