Abstract
Canthocamptus morimotoi Miura, a cave-dwelling harpacticoid species belonging to C. mirabilis species group, is fully redescribed and illustrated on the basis of the material newly collected from the type locality, Simpigul Cave, South Korea. C. morimotoi is the only genuine subterranean species in the C, mirabilis group, and claimed to be a relict species restricted to its type locality. The sexually isomorphic ornamentation of the outer terminal seta on the distal exopodal segment of male leg 4 and the well-developed spines on the disteromedial corner of anal somite are the most significant features differentiating this species from ther members of the mirabilis-group.