First Report of the Genus Quinquelaophonte Wells, Hicks and Coull, 1982 (Copepoda: Harpacticoida: Laophontidae) from China, with Description of a New Species.

The diversity of the species-rich copepod family Laophontidae T. Scott, 1905, is rarely investigated in China. Based on the recent collections from the coasts of the Yellow Sea in Shandong, two species of the genus Quinquelaophonte Wells, Hicks and Coull, 1982 were first reported from China, with one identified as new. The new species, Quinquelaophonte xinzhengi sp. nov., differs from other congeners by the following characteristics: female caudal ramus about 3.2 times as long as maximum width; P1 enp-2 bearing one claw and one minute seta; female P3 exp-3 with two inner setae, male P3 exp-3 with one inner seta; P4 exp-3 with one inner seta; and female P5 exopod bearing six setae. The COI genetic divergences between the new species and three closely related congeneric species all exceed 20% (21.5-22.3%), supporting their separate species status. Our samples of Q. enormis Kim, Nam and Lee, 2020, which are first found in China, show subtle differences with the original description of the type specimens from Korea on basis of maxilliped and P2 enp-1 with cuticular bulge subapically, female P3 and P4 without conspicuous morphological variation. This is also the first report of Quinquelaophonte from the China Seas.