title: Redescriptions of Spirosperma apapillatus and Embolocephalus nikolskyi (Annelida, Clitellata, Tubificinae) from Japan, with reference to distribution of papillate tubificines in Japanese freshwaters.
abstract: Based on new specimens, two freshwater papillate tubificines, Spirosperma apapillatus (Lastočkin in Lastočkin and Sokolskaja, 1953) and Embolocephalus nikolskyi (Lastočkin in Lastočkin and Sokolskaja, 1953) are redescribed, and geographic distributions are shown for these two species and E. yamaguchii (Brinkhurst, 1971) in the Japanese archipelago. A geographic cline from northern Hokkaido to northern Honshu is suggested by the distribution of simple-pointed ventral chaetae in Japanese E. nikoslkyi. That species is replaced by E. yamaguchii in the south, beginning in northern Honshu. Tubifex (Peloscolex) nomurai Yamatoto and Okada, 1940 , which was described from deep profundal bottoms in Lake Tazawa, Japan, may be ascribed to E. nikolskyi, or may be closely related; the definitive status is not settled.
authors.affiliation: Department of Natural Science, Faculty of Education, Hirosaki University, Hirosaki 036-8560, Japan. ohtaka@cc.hirosaki-u.ac.jp
authors.forename: Akifumi
authors.initials: A
authors.lastname: Ohtaka
authors.forename: Patrick
authors.initials: P
authors.lastname: Martin
mesh_terms: D000818:Animals; D000845:Annelida / Q000033:anatomy & histology* / Q000145:classification*; D005618:Fresh Water; D007564:Japan