Two Species of Koellikerina Medusae (Cnidaria, Hydrozoa, Anthomedusae) from Japan

Abstract

We fully described two Koellikerina species from shallow waters in Japan with illustrations and photographs. Koellikerina constricta (Menon, 1932), bearing characteristic bell constriction, expands its distribution to Kuchinoerabu Island, Kagoshima Prefecture (northern limit). Koellikerina bouilloni n. sp. is added to eight known species of the genus Koellikerina on the basis of an absence of bell constriction, a colorless body, and the presence of adaxial ocelli, perradial gonads, and a peduncle by examining a specimen from Tanabe Bay, Wakayama Prefecture and 18 specimens formerly collected from Papua New Guinea. Although bell constriction has been criticized as a taxonomic character, we conclude that it is reliable among Koellikerina because all the K. bouilloni specimens at variable developmental stages lack bell constriction and are clearly distinguishable from K. constricta.