Panaietis bobocephala sp. nov.

(Figs 1–3)

urn:lsid:zoobank.org:act: 1035E395-FE0B-41E7-A40C-45CD1615D839

Type material. Holotype: adult female (NSMT-Cr 26677), ex Haliotis asinina L. (Vetigastropoda: Lepetellida: Haliotidae), off Shirahama Beach (28°11'N, 129°16'E), the Oshima Strait, Amami Ohshima Island, 7 August 2015, leg. D. Uyeno, H. Uyeno, and M. Arai . Allotype: adult male (NSMT-Cr 26678), collection data same as holotype . Paratypes: 2 adult females and 1 adult male (NSMT-Cr 26679), collection data same as holotype .

Other material examined. 1 adult female (NSMT-Cr 26680), ex H. asinina, off Onna (26° 26'N, 127°46'E), the East China Sea, Okinawa, 26 October 2010, leg. D. Uyeno and T. Kobayashi .

Holotype adult female. Body (Fig. 1A) cyclopiform, 5.74 long, flattened dorso-ventrally with greatest width at first pediger; external segmentation distinct. Cephalosome wider than long, 1.06 × 2.05. First to fourth pedigers and six urosomites free.

Tergite of first pediger bearing pair of well-developed posterolateral lobes with pointed tip. Prosome 2.60 long. Genital somite (Fig. 1A, B) wider than long, 0.49 × 1.13, bearing pair of posterolateral lobes; paired genital openings situated on dorsal side (Fig. 1C). Abdomen (Fig. 1A, B) composed of four free somites, 0.33× 0.64, 0.35 × 0.65, 0.38 × 0.71, and 0.74 × 0.63, respectively. Caudal ramus (Fig. 1A, B, D) 3.50 times longer than wide, 0.70 × 0.20, bearing six setae. Egg sac (Fig. 1A) multiseriate, slightly curved.

Rostral area (Fig. 1E) without distinct apex. Antennule (Fig. 1F, G) 7-segmented; armature formula 4, 15, 3, 4, 6 + 1 aesthetasc, 2 + 1 aesthetasc, 7 + 1 aesthetasc; all setae naked. Antenna (Fig. 1H) 3-segmented, composed of coxobasis and 2-segmented endopod; coxobasis bearing single naked seta on distal margin; first endopodal segment bearing single inner protrusion with apical seta; second endopodal segment bearing three simple setae and single spatulate seta on inner margin, plus terminal claw, three claw-like spines, and two setae on distal tip. Labrum (Fig. 2A) bilobate. Mandible (Fig. 2B) bearing single lash-like seta with row of fine spinules on outer margin and apical serrated lash with two basal hyaline teeth. Maxillule (Fig. 2C) represented by unsegmented lobe bearing inner protrusion and two long and two short elements. Maxilla (Fig. 2D) 2-segmented; proximal segment rod-like, unarmed; distal segment bearing two sharp teeth and two basal setae. Maxilliped (Fig. 2E) indistinctly 2-segmented, composed of unarmed stout proximal portion and elongate distal portion with three small elements (Fig. 2E, F).

Legs 1 to 4 (Fig. 2 G–J) biramous, bearing 3-segmented rami. Leg armature formula as follows:

Intercoxal sclerites (Fig. 2 G–J) of legs 1 to 4 unarmed. All spines pointed. Both rami bearing pointed processes on outer margins. First and second endopodal segments of four legs bearing row of fine spinules on distal margins. Leg 5 (Fig. 3A) 2-segmented; proximal segment incompletely fused to fifth pediger with small simple seta; distal segment elongate bearing three small conical spines and single seta. Leg 6 not found.

Allotype adult male. Body (Fig. 3B) cyclopiform, 3.38 long, flattened dorso-ventrally with greatest width at cephalosome and first pediger; external segmentation distinct. Cephalosome (Fig. 3B) wider than long, 0.74 × 1.25. First to fourth pedigers and four free urosomites. Posterolateral corners of tergite on first pediger not well developed as that of female (Fig. 3B). Prosome (Fig. 3B) 1.61 long. Genital somite (Fig. 3B) wider than long, 0.26 × 0.58, with paired genital opercula (Fig. 3C). Abdomen composed of four free somites, 0.21 × 0.49, 0.19 × 0.48, 0.20 × 0.47, and 0.38 × 0.42, respectively. Caudal ramus (Fig. 3B) 3.69 times longer than wide, 0.53 × 0.14, with six setae.

Antennule, antenna, mandible, and maxilla as in female. Maxilliped (Fig. 3D) 4-segmented; first segment rodlike; second segment bearing two setae; third segment small with two elements; terminal claw curved bearing single basal seta, pointed process near distal tip, and row of fine spinules on inner margin. Armature formula of legs 1 to 4 as in female. Leg 5 as in female. Leg 6 (Fig. 3C) represented by two simple setae on genital operculum.

Variability. The morphology of the female paratypes and other material as in the holotype. The measurements of the body parts of paratypes and other material (n = 3) are as follows: body length 5.52–7.05 (6.07 ± 0.85); cephalosome length 0.83–0.98 (0.92 ± 0.08); cephalosome width 1.45–1.86 (1.70 ± 0.22); prosome length 2.46–3.20 (2.73 ± 0.41); genital somite length 0.41–0.46 (0.43 ± 0.03); genital somite width 1.03–1.08 (1.05 ± 0.02); first urosomite length 0.25–0.52 (0.35 ± 0.15); first urosomite width 0.56–0.65 (0.60 ± 0.05); second urosomite length 0.30–0.49 (0.41 ± 0.10); second urosomite width 0.57–0.70 (0.62 ± 0.07); third urosomite length 0.19–0.43 (0.32 ± 0.12); third urosomite width 0.61–0.72 (0.65 ± 0.06); anal somite length 0.59–0.72 (0.64 ± 0.06); anal somite width 0.50–0.69 (0.58 ± 0.10); caudal ramus length 0.69–0.77 (0.72 ± 0.04); caudal ramus width 0.19–0.22 (0.20 ± 0.01). Caudal ramus 3.46–3.60 (3.54 ± 0.07) times longer than wide.

The morphology of the male paratype as in the allotype. The measurements of the body parts of the paratype (n = 1) are as follows: body length 3.71; cephalosome length 0.69; cephalosome width 1.41; prosome length 1.67; genital somite length 0.28; genital somite width 0.59; first urosomite length 0.24; first urosomite width 0.54; second urosomite length 0.24; second urosomite width 0.51; third urosomite length 0.18; third urosomite width 0.50; anal somite length 0.49; anal somite width 0.42; caudal ramus length 0.57; caudal ramus width 0.16. Caudal ramus 3.52 times longer than wide.

Remarks. Panaietis bobocephala sp. nov. differs from P. incamerata Stebbing, 1900, P. yamagutii Izawa, 1976, P. doraconis Uyeno, 2016, and P. satsuma Uyeno, 2016 by having pointed spines on rami of legs 1 to 5 (vs. spatulate spines, Izawa 1976; Uyeno 2016). Panaietis haliotis Yamaguti, 1936 is distinguished from the new species by having following characters: the posterolateral corners of tergite on first pediger not protruded (vs. well-developed and protruded posteriorly); the maxilla bears three or four teeth on distal segment (vs. two teeth); leg 3 bears two setae on the third endopodal segment (vs. three setae); leg 4 bears three spines on the third endopodal segment (vs. two spines) (see Yamaguti 1936; Ho, 1981).

Attachment site. Mouth cavity and esophagus.

Etymology. The specific name of the new species, bobocephala, is the compound word of “ bob ” and “ cephala ” since the cephalosome and the first pediger of the copepod is reminiscent of a “bob” hairstyle.

Newly established Japanese name for species. Mimigai-no-haramushi.