Nephtys sachalinensis Alalykina & Dnestrovskaya 2015

Author diagnosis: "Prostomium rectangular with slightly convex anterior margin, antennae and palps arise near anterolateral angles of prostomium (Group II by Ohwada [37]). No eyespots visible. Terminal pharynx papillae: 20 bifid and 2 single. Subterminal pharynx papillae: no single median dorsal and ventral papillae; 22 rows of subterminal papillae, 4–5 papillae per row; median and proximal surface of pharynx covered with verrucae. Notopodial cirri from the first chaetiger continued back nearly to the end of the body, triangular at the anterior and subulate at the median and posterior chaetigers. Branchiae begin from the fourth chaetiger until the posterior end, without external basal process. Preacicular lobes of completely developed chaetigers simple, rounded and low. Acicular lobes distinctly bilobed from 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. Notopodial postacicular lobes at anterior chaetigers lingulate with round tips, more than two times longer than the acicular lobes; posteriorly obliquely rounded. Neuropodial postacicular lobes not more than two times longer than the acicular lobes at all chaetigers over the body; triangular elongated with rounded tips at medium chaetigers (also in large specimens at the anterior ones); posteriorly rounded. Slender pygidial cirrus about as long as last 6– 10 chaetigers. Preserved specimens light beige, living ones brown. Chaetae of two kinds: barred and chaetae with spines. Short barred chaetae are located in a preacicular row. The postacicular chaetae with spines are divided into spinose chaetae with “combs” and the chaetae with regular or irregular rows of spines. As well, there are the interramal bunches of chaetae with scattered fine denticles. Body length of the largest specimen: 108 mm, 112 chaetigers; width: 4–5 mm.