• anurans;
  • visceral pigmentation;
  • melanocytes


Amphibians share with other ectothermic vertebrates an extracutaneous pigmentary system consisting of melanin-containing cells in various organs and tissues. We describe the interspecific variation in the visceral pigmentation in three anuran species (Scinax similis, S. fuscovarius, and S. fuscomarginatus). We analyzed the visceral pigmentation of 15 adult males from each species during the reproductive period. The individuals were weighed and measured, and the pigmented visceral cells were classified and documented in stereomicroscope. The shape and amount of pigment cells differed among organs and also among species. Significant differences were detected in the cardiorespiratory system, digestory system, urogenital system, and lumbosacral peritoneum. In the urogenital system, the main difference was observed in the testes, in which only S. fuscomarginatus had varying degrees of pigmentation. Anat Rec, 2012. © 2011 Wiley Periodicals, Inc.