Newly Discovered Gastropod Hosts of Japanese Cytaeis Species (Cnidaria, Hydrozoa)

抄録

Colonial hydrozoans were newly found on the shells of five living gastropod species (Nassarius albescens, N. splendidulus, Vexillum exasperatum, Argyropeza izekiana and Sagami­lepeta sagamiensis), previously unknown as hydrozoan hosts in Japan. The hydrozoans included four Cytaeis species, identified by a molecular analysis of mitochondrial 16S ribosomal DNA sequences, as follows: C. kakinumae on N. splendidulus, Cytaeis sp. 1 on A. izekiana and S. sagamiensis, Cytaeis sp. 2 on N. albescens, and Cytaeis sp. 3 on V. exasperatum. The findings showed that Cytaeis species can exploit shells belonging to different gastropod families, although demonstrating strong host specificity.