New insights about ovarian pigmentation in Anura

Abstract

Amphibians have pigmented cells in organs beyond just skin. Their functions involve free radical neutralisation, early innate response, and a relationship with environmental temperature and UV light. In gonads, pigment containing-cells seem to be restricted mainly to the testes and related to sperm production. However, we report for the first time ovarian melanisation in Pseudis minuta and its ontogenetic changes in larval and postmetamorphic stages. Melanin containing-cells on the ovarian surface initially appear at early premetamorphic stages whereas in the cortex they occur later. In consecutive stages, melanin containing-cells were more evident among oocytes but without a clear pattern, being located randomly within the germinal epithelium or in the stroma. Although their function is unclear, a relationship with the fast acquisition of sexual maturity must be further explored.