Melanic pigmentation in ectothermic vertebrates: Occurrence and function

Abstract

Ectotherms have specialized chromatophores whose pigments are responsible for the different colors of the epidermis. Melanocytes are one type of chromatophore that produce and store melanin in organelles called melanosomes. In ectotherms, cells containing melanin pigments occur in several organs and tissues. These cells are found in the capsule and stroma of the organs, giving it a dark coloration. The function of visceral pigment cells is poorly known, but melanomacrophages are known to perform phagocytosis in hematopoietic organs and also act against bacteria, due to melanin. In addition, the distribution of visceral melanocytes varies with physiological factors, such as age, nutritional status; and also environmental one, such as temperature and photoperiod. On the other hand, the pigmentation in some organs seems to be conservative, and may help in phylogenetic reconstructions. © 2012 by Nova Science Publishers, Inc. All rights reserved.