Morphometric and molecular differentiation of Pimelodus grosskopfii and Pimelodus yuma (Siluriformes: Pimelodidae)

Abstract

Pimelodus grosskopfii and Pimelodus yuma, two species endemic to the Magdalena-Cauca basin in Colombia, overlap in the ranges of some of their diagnostic characters, which hampers their correct morphological identification. Aiming to help discriminate these species, this study conducted an integrative analysis using traditional and geometric morphometrics, phylogenetic analysis based on partial sequences of the mitochondrial cytochrome c oxidase subunit 1 gene (COI, cox1) and the identification of diagnostic Single Nucleotide Polymorphism markers (SNP). The species differ significantly in body geometry, allowing 100% discrimination, which was reinforced by a phylogenetic analysis that recovered well-supported monophyly of each species (posterior probability > 0.95). Additionally, the traditional morphometric results corroborated some previously reported diagnostic traits for both species and let us describe one non-overlapping ratio related to the adipose fin length. Three of five SNP markers had reciprocally exclusive alleles suitable for identifying each species. The morphometric and molecular methods conducted in this study constitute alternative tools for the correct discrimination of P. grosskopfii and P. yuma in the wild and in captive populations used for aquaculture.