A Systematic Study of the Genus Siriella (Crustacea:Mysida) from the Pacific and Indian Oceans, with Descriptions of Fifteen New Species

Fifty known species and four known varieties of the genus Siriella from the Pacific Ocean, the Indian Ocean and their marginal seas are revised. A nominal species, S. gibba is ranked in a junior synonym of S. brevirostris, because it is judged to be of an immature stage of female S. brevirostris. Three varieties, S. japonica var. izuensis, S. watasei var. koreana and S. watasei var. macropsis, are abandoned as nomen nudum, and proposed afresh as new species under the name of S. izuensis, S. koreana and S. macropsis, respectively. A variety, S. japonica var. sagamiensis is can-celed, because the description of this variety must have made based on immature forms of S. izuensis. The validity of S. robusta is questionable by reason that the description must have done on immature specimens. Siriella intermedia is canceled as nomen nudum, because the specific name, intermedia, has been preoccupied by a species which is known as S. armata at present. The following 12 species, S. akajimaensis, S. amamiensis, S. brucei, S. chaitiamvongae, S. essingtonensis, S. iii, S. longiarticulis, S. mulyadii, S. rimata, S. scissilis, S. seafdeci, and S. tenuiungula, are fully described herein as new species. Sixty-one nominal species of Siriella discussed in this article are classified into nine groups and five subgroups. Key to the species is given.