Creopelates nohmijimensis n. sp.

(Figs 1–3)

Type material. Holotype, female (NSMT –Cr 21191), ex Priolepis boreus (Snyder) ( Perciformes: Gobiidae), off Irukabana (34°13’N, 132°23’E), Nohmijima Island, Hiroshima, Seto Inland Sea, Japan; 15 m depth; 12 September 2009 by D. Uyeno. Paratypes, 2 females (NSMT –Cr 21192), ex P. boreus off Irukabana, Nohmijima Island, Hiroshima, Seto Inland Sea, Japan; 15 m depth; 12 September 2009 by D. Uyeno.

Description of postmetamorphic adult female. Body (Fig. 2 A) 7988–8906 (8447 ± 650) long (n = 3), curved at border of neck and trunk. Cephalothorax (Fig. 2 B–D) shorter than wide [634–724 (679 ± 64) × 1002–1248 (1086 ± 140)], oval bearing 4 lobes with digitate fringe. Neck region (Fig. 2 B) fringed with series of finely digitate lobes, arranged in about ten pairs. Trunk (Fig. 3 A) pyriform, longer than wide [3008–3380 (3189 ± 186) × 984 (0.27984 ± 0)], slightly curved dorsally, with anterior end narrowing towards “neck”, with posterior process (Fig. 3 B) located between oviduct orifices. Egg-sac uniseriate, curved on single plain (Fig. 1 B).

Antennule (Fig. 3 C) situated dorsally in proximity of antenna on anterior tip of cephalothorax; segmentation unclear, bearing 20 setae along anterior margin and 9 setae distally, 2 of which sharing common base, and 1 aesthetasc. Antenna (Fig. 3 D) 3-segmented, chelate, typical pennellid; proximal segment unarmed; middle segment bearing pointed protrusion along inner medial margin, terminal segment claw like. Mouth tube located near base of antenna. Maxillule (Fig. 3 E) bilobate; inner lobe with 2 distal setae and 1 basal seta; outer lobe bearing globular process. Maxilla (Fig. 3 F) 3-segmented; proximal segment bearing 1 distal projection; middle segment without armature; terminal segment covered with rows of spinules on posterior surface incompletely separated. Maxilliped absent.

Legs 1 to 4 situated at anterior end of neck region closely together, not separated by long distances. Legs 1 and 2 (Fig. 3 G, H) biramous, with both rami 2-segmented. Legs 3 and 4 (Fig. 3 I, J) uniramous, with 2- segmented exopods; leg armature formula as follows:

Protopod Exopod Endopod

Leg 1 1–1 1–1; 7 0–1; 7

Leg 2 1–0 1–1; 7 0–1; 7

Leg 3 1–0 0–0; 6

Leg 4 1–0 0–0; 5 ―

Some setae on distal segment of legs 1 to 4 blunt with papilliform tip.

Attachment site. The cephalothorax and neck region of the copepod were embedded in the host’s head and trunk musculature, while its trunk and egg sacs protruded into the water (Fig. 1 A, B).

Remarks. Creopelates is a monotypic genus, hitherto represented by C. floridus Shiino, 1958 (see Shiino 1958). The new species, C. nohmijimensis n. sp. can be easily separated from C. floridus by two characters: the cephalothorax bears four lobes ornamented with nodular and branching processes (Fig. 2 D), and leg 4 is situated close to the preceding legs.

Etymology. The specific name of the new species, nohmijimensis, refers to the type locality, Nohmijima Island in Hiroshima Bay (Seto Inland Sea), known for its high biodiversity.