Cirriformia septentrionalis, Jimi & Fujiwara & Kajihara, 2024

Cirriformia septentrionalis sp. nov.

[New Japanese name: Kita-mizuhiki] ( Figs 25–27 View Fig )

Material examined. Denshinhama: two of unknown sex, body length 76–87 mm, body width 2–3 mm, 265 chaetigers, 22 October 2014, coll. N. Jimi . Paratypes (NSMT-Pol P-953), COI INSD accession no . PP891560.

Huuren-ko: one of unknown sex, body length 122 mm, body width 3 mm, 249–301 chaetigers, 26 October 2014, coll. N. Jimi. Holotype (NSMT-Pol H-954), COI INSD accession no. PP891571.

Muroran-suishi-ura: two of unknown sex, body length 89–97 mm, body width 3–4 mm, 303 chaetigers, 23 October 2014, coll . N . Jimi . Paratypes (NSMT-Pol P-955), COI INSD accession no . PP891600.

Uenhirari: two of unknown sex, body length 46–54 mm, body width 2 mm, 230 chaetigers, 28 October 2014, coll . N . Jimi . Paratypes (NSMT-Pol P-956), COI INSD accession no . PP891605.

Description. Body length 46–122 mm and width 1–4 mm, 230–303 chaetigers, and color in life orange. Color in alcohol pale yellow ( Fig. 25A View Fig ). Several specimens with black pigmentation in anterior ventral zone. Body elongat- ed, dorsally inflated and grooved throughout, ventral surface not grooved. Eyes absent. Prostomium broad triangular ( Fig. 26). Paired nuchal organs located on prostomium. Peristomium with one annulation and some wrinkles, deeply grooved in junction between peristomium and chaetiger 1. Branchiae start from peristomium, one pair per segment. Branchiae arising from notopodial ridge, not shifting to mid-dorsal section. Notopodia and neuropodia separated, forming shoulders shifting from a position closer to dorsum to a more median position along midbody. Two groups of dorsal tentacles arising from chaetigers 6–7 (<89 mm length) or 7–8 (> 89 mm length); each group with 9–35 tentacles. Dorsal tentacles organized in two groups each. Notopodia and neuropodia with capillary chaetae and spines. Notochaeta: 2–16 capillary chaetae per fascicle along entire body, 2–5 spines ( Fig. 27A View Fig ) from chaetigers 52–80 and following chaetigers, spines short, slightly curved, blunt. Neurochaeta: 2–12 capillary chaetae per fascicle along entire body, 2–7 spines ( Fig. 27B View Fig ) present from chaetigers 29–54 and following chaetigers, spines short, slightly curved, blunt. Pygidium simple, with terminal anus.

Methyl Green Staining Pattern. The margin of prostomium was notably stained. Segment after tentacles were stained forming complete rings around segments, inter-segmental grooves not staining ( Fig. 25B, C View Fig ).

Etymology. The specific name is an adjective after the type locality (Hokkaido is the northernmost prefecture of Japan).

Distribution and habitat. Known from shallow water area of rocky beach around Hokkaido (~ 3 m).

Remarks. See remarks of C. akiyoae .