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Differentiation of Pimelodus grosskopfii and Pimelodus yuma

Posted: 31 May 2023, 06:28
by bekateen
Cristhian Danilo Joya, Ana María Ochoa-Aristizábal, José Gregorio Martínez, & Edna Judith Márquez. (2023). Morphometric and molecular differentiation of Pimelodus grosskopfii and Pimelodus yuma (Siluriformes: Pimelodidae). Neotrop. ichthyol., 21(02):e220072.

https://doi.org/10.1590/1982-0224-2022-0072
https://www.scielo.br/j/ni/a/MnNQWwRdGW ... N/?lang=en
Abstract
and , 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.
Keywords: Phylogenetic analyses; Freshwater fishes; Shape variation; SNPs markers; Cox1
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.
The figure below shows a pretty clear difference in adipose fin length, and also, if my eyes don't deceive me, in the relative position of the first ray of the anal fin relative to its point along the horizontal length of the adipose fin.