An Integrative Approach for Identifying Quinquelaophonte (Harpacticoida, Laophontidae) Species from Korea with the Description of a New Species

Abstract

Quinquelaophonte is a genus of laophontid harpacticoid, including 13 valid species around the world. Many of them are known to possess inter- and/or intra-individual variations in their swimming legs. During a survey of the meiofaunal biodiversity of Jeju Island in Korea, specimens of Quinquelaophonte were collected from an intertidal zone off the west coast of Jeju Island. This study examined the morphological characteristics and amplified partial sequence of four genes (18S rRNA, 28S rRNA, COX1, and CYTB). As with other Quinquelaophonte species, specimens of this new species showed variability in the chaetotaxy of their swimming legs in both sexes. There was a setal arrangement pattern in females that could be considered a standard, whereas male individuals showed two sets of the chaetotaxy on the fourth swimming legs. The molecular data confirmed that individuals belonged to a single species, regardless of morphological variations. The result of the morphological comparison showed that the new Quinquelaohponte species shared some characteristics with congeneric species but included some specific morphological characters different from its congeners. The new species was named Quinquelaophonte sominer sp. nov. and was presented with detailed descriptions, illustrations, and confocal micrographs. Furthermore, phylogenetic analyses were conducted using newly obtained data plus the sequences of other copepods and two Quinquelaophonte species. The result suggested that Q. sominer sp. nov. and two congeners were classified as branched lineages. This discovery brings the total number of species to three in the Northwest Pacific region.