Revision of the Ascidian Genus Herdmania (Urochordata : Ascidiacea) Inhabiting Japanese Waters

抄録

The pyurid ascidian genus Herdmania Lahille, 1888 has been known in Japanese waters by a single species, H. momus (Savigny, 1816), with two later proposed taxa treated as its junior synonyms. My detailed examination of many museum specimens, including most of those recorded from Japan in earlier publications and name-bearing types of the species to be compared, and also of newly collected material, reveals that these waters are inhabited by the following seven species : H. momus (Savigny), s. str. ; H. pallida (Heller, 1878), for which a lectotype is designated ; H. japonica (Hartmeyer, 1909), based on examination of syntypes, with Rhabdocynthia siphonalis Oka, 1933 as a probable junior synonym ; H. mauritiana (Drasche, 1884) (=H. insolita Monniot and Monniot, 2001), based on examination of the holotype of the former ; H. subpallida sp. nov. ; H. kiiensis sp. nov. ; and Herdmania sp. (=H. momus, sensu Millar 1975). A tabular comparison of these Japanese species, together with H. curvata Kott, 1952 (=H. contorta Monniot, 1992, syn. nov.), H. inflata (Van Name, 1918), and H. polyducta Monniot and Monniot, 1989, is compiled on the basis of a reexamination of the name-bearing types or paratypes of these latter species. Specific delimitations are based largely on the detailed structure of the gonads.