A new endemic species of Psalidodon Eigenmann (Characiformes: Acestrorhamphidae) from the upper rio Doce basin, Brazil

A new species of Psalidodon Eigenmann is described from an ichthyofaunistic poorly known portion of the upper rio Doce basin, in the state of Minas Gerais, southeastern Brazil. The new species is diagnosed and described using an integrative taxonomy approach. Psalidodon canaaensis new species is distinguished from its congeners by an unique combination of character states, which includes: presence of an adipose fin; a complete lateral line with 35–36 perforated scales; six horizontal scale rows between dorsal-fin origin and lateral line, five scales row between lateral line and pelvic-fin origin; 13–14 scales rows around caudal peduncle; presence of a vertically elongated humeral blotch; 18–24 branched anal-fin rays; one or two maxillary teeth bearing 3–5 cusps; males with elongated bony hooks on anal and pelvic fins, one per lepidotrichia segment; and a distinctive coloration pattern of the anal- and caudal- fins, with the anterior portion of the anal-fin olive green, and the caudal-fin greenish from the base to mid-length, followed by light red chromatophores on the distal portion of the fin-rays.

A haplotype network, and Maximum Likelihood analysis based on fragments of the Cytochrome c oxidase I (COI) gene for the new species and some of its congeners highly support it as constituting a separate lineage within Psalidodon. Psalidodon canaaensis has a restricted distribution, inhabiting a high-gradient stream with rapid water flow, subject to anthropogenic pressures. Presently, it is the only species of the genus endemic to the rio Doce basin, emphasizing the importance of surveys in understudied areas.