Nephtys sachalinensis sp. n. (Annelida: Nephtyidae): a new species from the upper sublittoral zone of northeastern Sakhalin Island, the Sea of Okhotsk

Abstract

A new species of nephtyid polychaetes Nephtys sachalinensis sp. n. from the upper sublittoral zone (at a depth of 10-107 m) off Northeast Sakhalin, the Sea of Okhotsk, is described. Diagnostic characters of adults are: an everted pharynx with 20 bifid terminal and 2 median simple terminal papillae; single median dorsal and ventral pharyngeal subterminal papillae absent; proximal and median parts of the pharynx are cov ered with verrucae; branchiae begin from the fourth chaetiger; acicular lobes are distinctly bilobed from the anterior chaetigers almost to the end of the body; each acicular lobe (both in noto and neuropodia) has one rounded outgrowth on its interramal side; subulate notopodial cirri at the median and posterior chaetigers; neuropodial postacicular lobes are no more than two times longer than the acicular lobes. The new species is compared with its related species.

Identification key to Nephtyidae (Annelida) of the Sea of Okhotsk

“…Thirteen of them belong to the most diverse genus Nephtys : N. assignis Hartman, 1950, N. brachycephala Moore, 1903, N. caeca (Fabricius, 1780), N. californiensis Hartman, 1938, N. ciliata , N. longosetosa Örsted, 1842, N. neopolybranchia Imajima and Takeda, 1987, N. paradoxa Malm, 1874, N. pente Rainer, 1984, N. punctata Hartman, 1938, N. rickettsi Hartman, 1938, N. sachalinensis Alalykina and Dnestrovskaya, 2015 and N. schmitti Hartman, 1938; one species belongs to Aglaophamus : A. malmgreni (Théel, 1879); and one to Micronephthys : M. minuta (Théel, 1879) ( Buzhinskaja 2013 , Alalykina and Dnestrovskaya 2015 ).…”