New species of the genus Trichosetodes Ulmer, 1915 (Trichoptera, Leptoceridae) from Ratanakiri province, Cambodia, based on morphological and molecular data

Abstract

Three new species of Trichosetodes, namely T. carmelae sp. nov., T. katiengensis sp. nov. and T. ratanakiriensis sp. nov. are described and illustrated by male specimens. The male genitalia of T. carmelae sp. nov. can be distinguished from the other 16 species of the genus found in Southeast Asia by the shape of the phallicata. The phallicata of T. carmelae sp. nov. bears a tuft of long hairs in the middle of the dorsal edge. Trichosetodes katiengensis sp. nov. can be distinguished from the other species in Southeast Asia by the shape of the phallicata which is divided into dorsal and ventral branches in lateral view, and T. ratanakiriensis sp. nov. by the characters of the left inferior appendage and the shape of segment IX. The posterior end of the left inferior appendage of T. ratanakiriensis sp. nov. is not forked and the ventral and lateral views of the posteroventral lobes of segment IX are rounded. Illustrations of male genitalia of Trichosetodes kampongspeuensis Malicky & Kong, 2020 are provided for comparison. The molecular diversity of new Trichosetodes species was analyzed using the mitochondrial large subunit ribosomal rRNA gene region (16S rRNA). In terms of their genetic divergence, T. ratanakiriensis sp. nov. and T. kampongspeuensis exhibited remarkable proximity, with only a 1.4% distance. On the contrary, T. carmelae sp. nov. displayed genetic disparity exceeding 6.3% when compared to both T. ratanakiriensis sp. nov. and T. kampongspeuensis.