Morphological and molecular characterization of two species of Laccotrephes (Hemiptera, Nepidae) from Eastern Ghats, India

Abstract

This study presents an integrative approach combining morphological and molecular techniques to identify and characterize two species of the genus Laccotrephes Stål — L. griseus Guérin Méneville) and L. ruber (Linnaeus) from the Eastern Ghats, India. Morphological differentiation was based on key characters such as body length, respiratory siphon length, prosternal structure, and male parameres. For molecular analysis, partial mitochondrial COI gene sequences (~620 bp) were amplified and analyzed using the Maximum Likelihood method in IQTREE. The resulting phylogenetic tree supported species-level divergence, with pairwise genetic distances ranging from 15.5 to 17.7 per cent between L. griseus and L. ruber, confirming their distinct taxonomic status. Intraspecific variation was minimal (<1%), while interspecific distances among other congeners showed clear genetic gaps. The integration of morpho-taxonomy and DNA barcoding underscores the value of a combined approach for accurate species delimitation and reveals potential cryptic diversity within the genus. This work enhances our understanding of aquatic Hemiptera biodiversity and provides a foundation for further taxonomic revisions in Laccotrephes.