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

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 covered 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 notoand 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.