First report of ocular heterochromia in the treefrog Boana albomarginata (Spix, 1824) (Anura: Hylidae), Atlantic Forest, northeastern Brazil

Abstract

The scientific literature on amphibian anomalies is large, but registered cases of amphibians’ ocular heterochromia are almost absent, even considering anecdotal records. In the Brazilian territory, only two cases of ocular heterochromia were formerly registered for amphibians, both for anurans, the first from the Atlantic Forest of northeastern Brazil and the second from the Amazonian region of northern Brazil. In the present account, we report two cases of ocular heterochromia in the hylid treefrog Boana albomarginata, both from the Atlantic Forest biome, Bahia state, northeastern Brazil, representing the first record of ocular heterochromia for this species and the third case registered for an amphibian’s species in Brazil. One eye of each observed specimen had an unusually flashy and homogeneous blue-colored iris, filling its entire surface or only its lower half, representing cases of complete and sectoral heterochromia, respectively. Furthermore, the unusual flashy blue iris was only detectable during daylight, when the iris background color was white. At night, the standard copper to golden iris background color remains unchanged, and the blue color cannot be detected. No other detectable anomalies or unusual behaviors were observed for both specimens. This is the first report of amphibian ocular heterochromia represented by a flashy blue color iris and limited to a daylight iris color pattern. Further studies are necessary to determine the nature of this anomaly and its potential consequences for the specimen and the species.