ABSTRACT
Brazilian subterranean ichthyofauna is remarkable worldwide not only due to the species richness, including troglomorphic and non-troglomorphic fi shes, but also for the high ecological and evolutionary diversity, without a taxonomic correlation. More than 25 troglomorphic species showing different degrees of morphological specialization are currently known to occupy a large diversity of habitats, from epikarst to fast fl owing baselevel streams, in different karst regions. Such areas are submitted to distinct, sometimes contrasting climates, thus subterranean fi shes must adapt to different ecological conditions, varying from accentuated food shortage, frequently seasonal, to a relative climatic stability and, in some cases, abundance of food resources. The fi rst known Brazilian troglobite was the heptapterid Pimelodella kronei, from the Upper Ribeira karst area, southern São Paulo State (SE Brazil), described as Typhlobagrus kronei Ribeira, 1907. The blind catfi sh from Iporanga was also the fi rst South American subterranean organism studied in great detail, by Pavan (1945) and later on, by Trajano (1987) for their PhD theses, which included morphology, behavior and ecology analyzed within an evolutionary context. Therefore, this troglobitic
fi sh represents an important historical reference in the development of Brazilian Subterranean Biology. In the last two decades, studies on the taxonomy, natural history, population ecology and behavior of Brazilian troglobitic fi shes have multiplied, encompassing several species living in different kinds of subterranean habitats and showing different degrees of reduction of eyes and melanic pigmentation (classical “troglomorphisms”, Trajano 2005). However, this still represents a relatively small part of what there is to be investigated. Herein, we present an overview on the state of art of the knowledge on Brazilian subterranean fi shes, including both troglomorphic (morphologically specialized), probably troglobitic (exclusively subterranean) species, and non-troglomorphic, either troglophilic, trogloxenic or accidental fi shes in caves.
