Revision of Diplocirrus Haase, 1915, including Bradiella Rullier, 1965, and Diversibranchius Buzhinskaja, 1993 (Polychaeta, Flabelligeridae)

Diplocirrus Haase, 1915, includes flabelligeridscylindrical to club-shaped bodies, with cirriform papillae, multiarticulate chaetae in both parapodial rami, 8 branchial filaments of two types (thick and rarely lamellate, or cirriform), gonopodial lobes in chaetigers 5 or 6, or multiple gonopores along some anterior chaetigers. Bradiella Rullier, 1965, has included only the type species: B. branchiata Rullier, 1965, described from Eastern Australia. The original description has been overlooked and it lacked enough details on branchial and chaetal features. Diversibranchius Buzhinskaja, 1993, with D. nicolaji Buzhinskaja, 1994, as the type species, was introduced for a similar species from the Japan Sea. These two monotypic genera share the same morphologic features with Diplocirrus, and are herein regarded as its junior synonyms. As herein redefined, Diplocirrus includes, besides its type species, D. glaucus (Malmgren, 1867)from Scandinavia : D. branchiatus (Rullier, 1965), comb. n. from Queensland, Australia, D. capensis Day, 1961 from South Africa, D. erythroporus Gallardo, 1968 from Vietnam, D. hirsutus (Hansen, 1882) from Arctic and subarctic regions, D. incognitus Darbyshire & Mackie, 2009 from South Africa, D. kudenovi sp. n. from off Western Mexico, D. longisetosus (von Marenzeller, 1890) restricted to the Bering Sea, D. micans Fauchald, 1972 from deep water off Oregon and Western Mexico, D. nicolaji (Buzhinskaja, 1994), comb. n. from the Japan Sea, D. normani (McIntosh, 1908), comb. n. from Scandinavia, D. octobranchus (Hartman, 1965), comb. n. from off New England, and D. stopbowitzi Darbyshire & Mackie, 2009 from the Irish Sea.