First Molecular Characterisation and SEM Observations of Lamproglena barbicola from Labeobarbus altianalis in the Nyando River, Kenya

Abstract

A supplemental description of Lamproglena barbicola Fryer, 1961 is provided based on specimens collected from the gills of Labeobarbus altianalis (Boulenger, 1900) from the Nyando River, Lake Victoria Basin, Kenya, using an integrated approach of scanning electron microscopy (SEM) and molecular analysis (18S, 28S rDNA, and cox1 gene regions). Morphologically, the specimens conform to L. barbicola and closely resemble Lamproglena hoi Dippenaar, Luus-Powell & Roux, 2001; however, SEM revealed a previously undescribed feature on the uniramous antennule in L. barbicola, namely indistinctly three-segmented, tapering from a broad base to the apex, basal segment much longer than distal, comprising 14 setae of varying sizes, ventral laterally, absence of distinctive anterior fringe of setae on the antennule, as well as several characters that differentiate L. barbicola from L. hoi, including 5 setae at the basal endopod of leg one, five cuticular protuberances in the oral region, 19 setae on the basal antennular segment, and 10 setae on the distal segment, with 1 seta on each ramus. The phylogenetic analysis confirms L. barbicola as a sister taxon of L. hoi, supporting their close relationship. The genetic divergence presented as the uncorrected genetic p-distances between L. barbicola and L. hoi are 23.1% and 0.45% for cox1 and 28S rDNA regions, respectively, with observed nucleotide differences of 145 and 3 bp between the sequences, respectively. There was no interspecific variability detected in the 18S rDNA sequences. This study provides novel molecular sequences and the first high-resolution SEM images, which reveal additional taxonomic features for L. barbicola, establishing a robust reference for future identification.