Relationships of a new South American catfish genus (Siluriformes: Trichomycteridae) on the verge of extinction providing insights about role of Andean uplift in trichomycterine diversification

Trichomycterinae catfishes are widely distributed in the Neotropics, with a greater species concentration in the Andes and eastern South American mountain ranges. The focus of the present study is a trichomycterine clade endemic to a region of central Brazil under severe process of environmental degradation. It is provisionally placed in ‘Trichomycterus’, but previous studies indicate that it is closely related to Andean genera. We performed a multigene phylogenetic analysis including representatives of all main trichomycterine lineages and a biogeographical analysis using ancestral area reconstruction in a time-calibrated phylogeny, aiming to test the positioning of that unnamed clade, here described as a new genus, and the role of Andean uplift in trichomycterine diversification. The analysis indicated an Andean origin for Trichomycterinae during the Eocene (about 50 Ma) and occurrence of dispersal events from the Andes to other Neotropical areas and in the opposite direction, corroborating multiple biotic exchange as reported for other organisms. The divergence time between the new genus lineage and its sister group, a southern Andes clade, was estimated to have occurred in the Oligocene, about 30 Ma, thus synchronous with the uplift of the Central Andes and the formation of the Central Andean Orocline adjacent to Central Brazil.