﻿AbstractSpecies ofKaloplocamusBergh, 1880 are enigmaticNudibranchiasea slugs, and only two valid species are reported in the northwestern Pacific.Kaloplocamusjaponicus(Bergh, 1880) was initially described based on alcohol-fixed specimens. In the latest revision ofKaloplocamus, it was synonymized withKaloplocamusramosus(Cantraine, 1835). Recently, several nudibranchs were collected from Tianheng, Shandong Province, China, and one of them is identified as an undescribed species described here asKaloplocamusalbopunctatussp. nov.based on integrated approaches incorporating morphological observations, internal anatomy, and phylogenetic analyses of two mitochondrial (COI,16SrRNA) genes. The other species is identified asK.japonicusBergh, 1880 based on the anatomy of the reproductive system. The new speciesK.albopunctatussp. nov.is similar toK.ramosusin having a bright orange-red color pattern but differs significantly in the structure of appendages and reproductive system.Kaloplocamusjaponicuscan be easily distinguished from otherKaloplocamusspecies by its translucent, white-pink coloration and unique features of the female reproductive organ. Both species are supported as distinct species in all molecular analyses. The phylogenetic analyses propose a new estimate of the relationship betweenKaloplocamusandPlocamopherus, and the evolution of bioluminescence withinTriophinaeis discussed. Our results also suggest cryptic biodiversity within theK.ramosusspecies complex.