A new pelvic-less species of Cambeva (Siluriformes: Trichomycteridae) from the Rio Paranapanema drainage, southern Brazil, supported by integrative taxonomy

Recent studies have indicated a strong tendency to pelvic-fin loss in Cambeva, with nine species lacking both pelvic fin and support. Herein we describe another pelvic-less species, collected in the Rio Paranapanema drainage, upper Rio Paraná basin, sharing a similar unique colour pattern with C. pascuali, endemic to the same drainage and also lacking pelvic fins. A molecular approach for species delimitation, using a cytochrome b fragment of 970 bp, corroborated both species as distinct taxa, exhibiting a genetic distance of 4.9–5.1 %.The two species morphologically differ from each other by the relative position of the dorsal and anal fins, relative position of unpaired fins and vertebrae, number of jaw teeth, and the relative length of the autopalatine posterolateral process and the lateral parurohyal process. Like C. pascuali, individuals of the new species were collected buried in vegetal debris deposited on the bottom sandy substrate. Vegetal debris were composed of fallen leaves and branches from the riparian forest, suggesting a close dependence on this vegetation for the survival of the new species. Signals of environmental degradation were recorded in the type locality area of the new species. We suggest that species having unique ecological preferences related to other aquatic organisms that are vulnerable should be regarded with close attention in analyses of conservation priorities.