Cirriformia satoi, Jimi & Fujiwara & Kajihara, 2024

Cirriformia satoi sp. nov.

[New Japanese name: Doro-mizuhiki] ( Figs 10–12 View Fig )

Material examined. Asadokoro: one of unknown sex,

body length 32 mm, body width 1 mm, 205 chaetigers, 10 June 2014, coll . N . Jimi . Paratype (NSMT-Pol P-933), COI INSD accession no . PP891558.

Higatakouen: two of unknown sex, body length 42–52 mm, body width 2 mm, 235–308 chaetigers, 28 June 2014, coll . N . Jimi . Paratypes (NSMT-Pol P-934), COI INSD accession no . PP891563.

Honjyou: one of unknown sex, body length 87 mm, body width 2 mm, 288 chaetigers, 24 June 2014, coll. N. Jimi. Holotype (NSMT-Pol H-935), COI INSD accession no. PP891568.

Issiki: one of unknown sex, body length 32 mm, body width 2 mm, 109 chaetigers, 3 June 2014, coll . N . Jimi . Paratype (NSMT-Pol P-936), COI INSD accession no PP891575

Siokawa: one of unknown sex, body length 116 mm, body width 7 mm, 338 chaetigers, 2 June 2014, coll . N . Jimi . Paratype (NSMT-Pol P-937), COI INSD accession no . PP891598

Souzugawa: one of unknown sex, body length 68 mm, body width 2 mm, 300 chaetigers, 18 June 2014, coll . N . Jimi . Paratype (NSMT-Pol P-938), COI INSD accession no . PP891599

Description. Body length 32–116 mm and width 1–7 mm, 109–338 chaetigers, and color in life orange. Color in alcohol pale yellow ( Fig. 10A View Fig ). Several specimens with black pigmentation in anterior ventral zone. Body elongated, dorsally inflated and grooved throughout, ventral surface not grooved. Eyes absent. Prostomium rounded ( Fig. 11). 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, few. Branchiae arising from notopodial ridge, in posterior segments, inserted at discrete distance 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 5–6 (<42 mm length) or 6–7 (> 42 mm length); each group with 4–10 tentacles. Dorsal tentacles organized in two groups each. Notopodia and neuropodia with capillary chaetae and spines. Notochaeta: 3–12 capillary chaetae per fascicle along entire body, 2–4 spines ( Fig. 12A View Fig ) from chaetigers 110–235 and following chaetigers, spines short, slightly curved, blunt. Neurochaeta: 3–8 capillary chaetae per fascicle along entire body, 3–7 spines ( Fig. 12B View Fig ) present from chaetigers 31–48 and following chaetigers, spines short, slightly curved, blunt. Pygidium simple, with terminal anus.

Methyl Green Staining Pattern. The margin of prostomium and edge of dorsal area of chaetiger 2–4 were notably stained. Segment after tentacles were stained forming complete rings around segments, inter-segmental grooves not staining ( Fig. 10B, C View Fig ).

Etymology. This species is named after Dr. Masanori Sato in recognition of his great taxonomic works about Japanese polychaetes especially around tidal flats.

Distribution and habitat. Known from tidal flats in the area of Pacific Ocean side of Japan.

Remarks. This species has dorsal tentacles in chaetigers 5–6 or 6–7 and branchia starting from peristomium. Cirriformia chehocensis (Grube, 1877) is incompletely described as the chaetiger number of the first pair of branchiae is not given in the original description, but dorsal tentacles arise from one segment (5 or 6). This character helps discrimination C. chehocensis from C. satoi .

This species resembles C. petersenae sp. nov. in that dorsal tentacles arise from chaetigers 5–6 or 6–7 and branchia starting from peristomium. This species can be discriminat- ed from C. petersenae by neuropodial spine start from more posterior chaetigers (110–235) and shape of prostomium (rounded vs. broad triangular).