Fish species living at the subterranean environment share particular features that can be related to its life habit in a distinctive selective regime, characterized by environmental constraints. Studying the patterns of morphological modification on these species may help to elucidate questions about how colonization of the subterranean environment is accomplished and how organisms respond to this new selective regime. Troglomorphic species from the genus Ituglanis (Siluriformes: Trichomycteridae), the most species-rich of brazilian subterranean ictiofauna, constitute great models to the study of morphological and evolutionary patterns, especially because of its occurrence in near geographic areas, its putatively recent isolation at the subterranean environment, and because they exhibit troglomorphic characters in different degrees, probably resulting from parallel evolution. In this sense, the proposed study aims to analyze what morphological and evolutionary patterns for external (skin pigmentation, paired fins and body length) and sensory-related characters (eyes, barbells, lateral line and encephalon) can be found for the subterranean species of the genus Ituglanis, how these patterns can be identified on these species and what is the relationship between these morphological modifications and the subterranean life habit. All five subterranean species described for the genus, Ituglanis passensis, I. bambui, I. epikarsticus, I. ramiroi e I. mambai, plus one new undescribed species, will be compared with epigean ones to identify the characters modified after colonization of the subterranean environment. The following characters will be analyzed: eyes, skin pigmentation, barbels, lateral line, paired fins, body size, encephalon and body asymmetry. Results will be discussed by means of comparative description and statistical analysis, according to suitable situation. We expect to identify significant differences between subterranean and epigean species for the cited characters, with distinctive evolution patterns on the different species.
News published in Agência FAPESP Newsletter about the scholarship: