A new species of Ituglanis (Siluriformes: Trichomycteridae) from the Uruguai River basin closely related to congeners from Atlantic coastal drainages

Abstract

A new species of Ituglanis is described from the upper and lower Uruguai River basin, supported by both morphological and molecular evidence. The new species is distinguished from most congeners by the body color pattern consisting of two spotted layers of pigmentation over a yellowish background: inner layer with rounded dark brown spots, somewhat coalescent, equivalent in size to the eye circumference, covered by the outer layer composed of several smaller rounded brown spots. This coloration, in combination with mitochondrial DNA (Cytochrome c oxidase subunit I: COI) analysis, suggests a close phylogenetic relationship between the new species and three congeners from Atlantic coastal drainages: Ituglanis boitata, I. amphipotamus, and I. proops. The new species differs from these three congeners by a combination of characters related to the length and shape of the interopercular odontophore; number of odontodes, number of pectoral-fin rays, and morphology of the cephalic laterosensory system.

Keywords:
COI; Conservation; Freshwater ecoregions; Iterative taxonomy; Trichomycterinae