The monophyly of Crenuchinae and description of two new species ofPoecilocharax(Teleostei: Crenuchidae) based on phenotypic and genotypic evidence

Abstract

Crenuchinae is a subfamily of the fish family Crenuchidae distributed in the Amazon Basin with pronounced sexual dimorphism and exuberant colour patterns. Recent fieldwork in the tributaries of the Rio Aripuanã drainage, a large tributary of the Rio Madeira (Amazon Basin), resulted in the discovery of two distinctive, undescribed species of the crenuchin genus Poecilocharax, which are formally described herein, combining morphological and molecular data. These are the first representatives of Crenuchinae discovered after a gap of 57 years and the first records of Poecilocharax from the tributaries of the right bank of the Rio Amazonas draining the Brazilian crystalline shield. Based on a taxonomic review including all species of the subfamily, we provide an expanded morphological diagnosis for Crenuchinae. This now includes characteristics related to the lateral-line canals of head and body, the number of dorsal-fin rays and sexually dimorphic traits. In addition, we review previous characteristics used to diagnose Crenuchus and Poecilocharax, providing comments on their polarity and distribution across the subfamily. A dichotomous key is provided for the first time for species of Crenuchinae.