Abstract
A species of marine nematode, Chromadorina hiromii sp. nov., is described based on cultured specimens found in an aquarium containing medusae and polyps of Aurelia aurita (Linnaeus, 1758). The native habitat of the species is unknown, but certainly somewhere on the Pacific coast of Central Japan. Chromadorina hiromii resembles C. cervix (Wieser, 1951) and C. bergensis (Allgen, 1932) but differs from them in having a robust gubernaculum with well-cuticularized lateral pieces and five or six precloacal supplements in the male. Chromadorina hiromii is the second species of the genus known from Japan, the first being C. inversa Wieser, 1955, which was described from a single female collected at Shirahama. An examination of topotypic male specimens of C. inversa is required to understand its relationship to C. hiromii.
