Top mountain areas of subtropical southern Brazil sheltering four new small-ranged catfishes (Siluriformes, Trichomycteridae): relationships and taxonomy

Mountainous regions typically host a great diversity of small-ranged species, often contributing for delineating world biodiversity hotspots. Species of trichomycterine catfishes have been recorded for several high-altitude areas of tropical South America, but field inventories in top mountains of southern Brazil are still rare. Here we report four new small-ranged species collected in streams of the Rio Iguaçu at Serra do Espigão (RISE) in altitudes between about 970 and 1020 m asl, one in the eastern portion of RISE and three in the western portion. A molecular phylogenetic analysis indicated that these species belong to the Cambeva beta-clade, which comprises all species endemic to the Rio Iguaçu drainage, but together not forming a monophyletic group. The analysis also indicated that species endemic to high altitudes are variably related to species from lower altitudes. The only eastern RISE species appears in a basal position of a well-supported clade (Cambeva beta1-clade), with the western RISE species appearing in a subclade of the Cambeva beta1-clade with species occurring in a vast area of southern Brazil. New species are diagnosed by combinations of morphological character states, including meristic, colouration, latero-sensory system, and osteological data.