Remarkable biodiversity of flabelligerids in Japan: seven new species of Diplocirrus (Annelida: Flabelligeridae) from Japanese waters Author Jimi, Naoto Author Fujiwara, Yoshihiro Author Kajihara, Hiroshi text Zootaxa 2017 2017-10-19 4337 3 journal volume 31802 10.11646/zootaxa.4337.3.2 53927ce7-a83a-4a6d-929b-b4269892bd23 1175-5326 1024922 D927258A-BF86-4E22-8725-8DD2CADAD3A0 Diplocirrus imajimai sp. nov. (New Japanese name: Imajima-konbou-habouki) ( Figure 2 ) Type material. Holotype : NSMT-Pol H-635, off Otsuchi St. 2, 215 m depth, collected by NJ, COI sequence could not be determined. Description. Holotype incomplete, 11 mm long, 1 mm wide (in chaetiger 10), 18 chaetigers. Body with first 9 chaetigers swollen, thereafter cylindrical ( Fig. 2A ). Tunic whitish in ethanol without sediment particles ( Fig. 2B ). Digitate papillae abundant, longer than wide, short, in median chaetigers about 1/25 as long as notochaetae and 1/4 as long as lateral papillae in chaetal lobe, arranged in 4–5 transverse rows per segment. Cephalic hood transparent, without papillae. Gonopodial lobe and gonopores absent. Posterior region tapered; anal part lost in holotype . Two types of branchiae present: dorsal branchiae 0.8 mm long, thick, with one lobe in internal side, not lamellate ( Fig. 2C ); ventral branchiae 0.9 mm long, thick, smooth, not lamellate ( Fig. 2D ). Palps 1.0 mm long, grooved. Upper and lateral lips well developed. Caruncle poorly projected, not separating dorsal branchiae. Eyes absent. Nephridial lobes present, whitish ( Fig. 2E ). Parapodia poorly developed, chaetae emerging from body wall; notopodia with no lateral papillae on anterior side and 1–3 lateral papillae on posterior side; neuropodia with no lateral papillae on anterior side and 1–2 lateral papillae on posterior side. Cephalic cage developed (1 st notochaeta 1.2 mm in length). Notochaetae 5–8 per bundle, multiarticulate ( Fig. 2F ) with 15–19 articles in chaetiger 19; tip capillary. Neurochaetae 4–6 per bundle, multiarticulate ( Fig. 2G ) with 12–15 articles in chaetiger 19, rounded projection poorly developed; subdistal article 3–4 times longer than wide; tip slightly falcate. Distribution. Only known from type locality, off Otsuchi, 215 m depth. Etymology. This species is named after Dr. Minoru Imajima in recognition of his great taxonomic works about Japanese polychaetes. The specific name is a noun in the genitive case. Remarks. Diplocirrus imajimai sp. nov. resembles D. capensis Day, 1961 in the following features: i ) body papillae are short, longer than wide, and abundant, ii ) body is not covered with sediment particles, and iii ) gonopores are absent. The cephalic cage of D . imajimai sp. nov. is well developed (longer than body wide), whereas it is poorly developed in D . capensis (chaetiger 1 shorter than following ones). Diplocirrus capensis has black eyes, whereas D . imajimai sp. nov. does not have eyes.