DNA barcoding and phylogeny of Trichomycterus sp. (“life”) (Siluriformes: Trichomycteridae) from the Jequetepeque River, Peru

Abstract

The objective of this study was to molecularly identify Trychomycterus sp. (“life”) from the Jequetepeque River using DNA barcoding and to reconstruct its phylogenetic relationships. For this purpose, six specimens of “life” were collected near the town of Magdalena (-7.2509344, -78.6752351) using a cast net, with sampling conducted during both daytime and nighttime hours. Specimens were taxonomically identified, photo-documented, and preserved in 96% ethanol. Caudal fin tissue was obtained from all individuals; however, high-quality DNA was recovered from only five specimens. The mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified and sequenced. Chromatograms generated by Sanger sequencing were edited using Chromas v2.6.6, and consensus sequences were assembled in AliView. Sequences were subsequently aligned with the MUSCLE algorithm implemented in MEGA X, together with homologous sequences retrieved from the NCBI GenBank database. A total of 36 sequences (680 bp) were included in the analyses. Ituglanis boitata (KY857994) from Brazil was use as the outgroup. MEGA X was employed to select the best-fit evolutionary model for maximum likelihood (ML) and Bayesian inference (BI) analyses. Phylogenetic reconstruction was performed using RAxML GUI v2.0 with 1,000 bootstrap replicates under the GTR+T+I model (general time reversible with gamma-distributed rate variation and a proportion of invariant sites). The results indicate that Trichomycterus sp. from the Jequetepeque River exhibits greater genetic affinity to Trichomycterus striatus than to Trichomycterus punctulatus. Based on these findings and previous evidence, species diversity within this genus appears to be underestimated in rivers of the Peruvian Pacific slope, highlighting the need for comprehensive taxonomic and molecular studies of Trichomycterus species inhabiting these systems. 2026