A new endemic pearl cichlid of the 'Geophagus' brasiliensis (Cichliformes: Cichlidae) species group from the Piranga River, upper Doce River basin, southeastern Brazil.

A new species of pearl cichlid of the 'Geophagus' brasiliensis species group, endemic to the Piranga River, a major tributary of the upper Doce River basin in the state of Minas Gerais, southeastern Brazil, is herein described. The new species is delimited using an integrative approach, with molecular-based species delimitation methods coupled with morphological diagnosis. For this, we developed a matrix containing 27 sequences of the mitochondrial gene cytochrome c oxidase subunit I (COI) of species of the 'G.' brasiliensis species group obtained from GenBank and three new sequences generated in this work. The species delimitation method applied to the morphological characters was Population Aggregation Analysis (PAA), and the species delimitation methods applied to the nucleotide sequences were the branch coalescence methods: Bayesian Poisson Tree Processes (bPTP), General Mixed Yule Coalescent (GMYC) single-threshold and GMYC multi-threshold. The three molecular-based species delimitation methods corroborate that the haplotypes of 'Geophagus' from the Piranga River represent a new species distinguished from all other in the 'G.' brasiliensis species group by exclusive presence of clear, rounded spots in the posteriormost dorsal-fin rays in fixed adult specimens, and the combination of the following morphological characters: long snout (46.22%-52.74% of head length), tall head (94.08%-101.15% of head length), terminal mouth, 25 or 26 longitudinal scales on the E0 series, 14 or 15 spines on the dorsal fin, absence of bluish dots on the most anterior soft rays of the anal fin in live specimens and absence of bluish and longitudinal lines in the basal region of the caudal fin of live specimens. This work is the first description of a new species of the 'G.' brasiliensis species group from the Doce River basin.