Panaietis doraconis, Uyeno, Daisuke, 2016

Uyeno, Daisuke, 2016, Copepods (Cyclopoida) associated with top shells (Vestigastropoda: Trochoidea: Tegulidae) from coastal waters in southern Japan, with descriptions of three new species, Zootaxa 4200 (1), pp. 109-130 : 115-119

Panaietis doraconis n. sp.

( Figs 4–6 )

Type material. Holotype: adult female ( NSMT –Cr 24622), ex Tectus pyramis (Born, 1778) ( Vetigastropoda : Trochoidea: Tegulidae ), off Saneku (28°12'N, 129°12'E), Kakeroma Island, Oshima Strait, 27 April, 2015, leg. D. Uyeno, S. Yokoyama . Allotype: adult male ( NSMT –Cr 24633), collection data same as holotype . Paratypes: 2 adult females and 1 adult male ( NSMT –Cr 24634), collection data same as holotype .

Additional material. 1 adult female and 1 adult male (KAUM-AT-288), ex T. pyramis , off Yoron Island (27° 1'N, 128°26'E), North Pacific Ocean , 16 May, 2015, leg. D. Uyeno ; 2 adult females ( RUMF –ZC-04355), ex T. pyramis , off Manza (26°30'N, 127°50'E), Onna, Okinawa Island, East China Sea, 30 March, 2012, leg. D. Uyeno ; 3 adult females and 1 adult male ( NSMT –Cr 24625), ex T. pyramis , off Manza (26°30'N, 127°50'E), Onna, Okinawa Island, East China Sea, 23 March, 2012, leg. D. Uyeno ; 3 adult females ( NSMT –Cr 24624), ex T. pyramis , off Hakamagoshi (31°35'N, 130°35'E), Sakurajima Island, the Kagoshima Bay, 20 September, 2015, leg. D. Uyeno .

Description of holotype. Adult female. Body ( Fig. 4 A) cyclopiform, 7.71 long, with greatest width at cephalosome; external segmentations distinct. Cephalosome distinctly articulated from first pedigerous somite, wider than long, 0.70 × 0.75. First to fourth pedigerous somites and urosomites free. Prosome 2.14 long. Genital somite bearing one pair of lateral lobes ( Fig. 4 A, C), 0.52 × 0.69; genital openings situated on dorsal side. Abdomen composed of four free somites, 0.62 × 0.52, 0.76 × 0.52, 0.70 × 0.47, and 1.21 × 0.33, respectively. Caudal ramus ( Fig. 4 A, D) 7.24 times longer than wide, 1.13 × 0.16, with six setae.

Rostrum ( Fig. 4 B) triangular without distinct apex. Antennule ( Fig. 4 E) 7-segmented; armature formula 4, 15, 4, 4, 6 + 1 aesthetasc, 2 + 1 aesthetasc, 7 + 1 aesthetasc; all setae small and naked. Antenna ( Fig. 4 F) 3-segmented, composed of coxobasis and 2-segmented endopod; coxobasis large, bearing naked seta; first endopodal segment bearing small, naked seta on inner margin; second endopodal segment bearing four inner setae, inner fused claw, three claws, and two long setae. Labrum ( Fig. 4 G) broad, bearing pair of posterior lobes. Mandible ( Fig. 5 A) bearing lash-like serrated inner setiform element and apical serrated setiform element with two hyaline outer teeth at outer base. Maxillule ( Fig. 5 B) represented by simple lobe armed with spherical protrusion and simple elements. Maxilla ( Fig. 5 C) 2-segmented; basal segment unarmed; terminal segment bearing row of spinules, five sharp processes, and two small setae. Maxilliped ( Fig. 5 D) 2-segmented, composed of unarmed syncoxa and rod-shaped basis bearing single apical blunt element.

Legs 1 to 4 ( Fig. 5 E–H) biramous, with 3-segmented rami. Leg armature formula as follows:

Coxa Basis Exopod Endopod

Leg 1 0-0 1-0 I-0; I-0; III, I, 3 0-0; 0-0; II, 1, 2 Leg 2 0-0 1-0 I-0; I-0; III, I, 3 0-0; 0-0; II, I, 2 Leg 3 0-0 1-0 I-0; I-0; III, I, 3 0-0; 0-0; III, I, 2 Leg 4 0-0 1-0 I-0; I-0; III, I, 3 0-0; 0-0; III, I, 1 Intercoxal sclerite ( Fig. 5 E–H) of legs 1 to 4 unornamented. All spines spatulate. Both rami of legs 1 to 4 bearing rows of fine spinules present on base of spines. Leg 5 ( Fig. 5 I) consisting of dorsolateral seta on fifth pedigerous somite and free exopod; exopod elongate, rod-shaped, bearing three blunt spines and naked seta. Leg 6 ( Fig. 4 C) represented by two small elements at genital opening.

Description of allotype adult male. Body ( Fig. 6 A) cyclopiform, 4.06 long, depressed dorso-ventrally with greatest width at cephalosome; external segmentations distinct. Cephalosome distinctly articulated from first pedigerous somite, slightly wider than long, 0.57 × 0.61. First to fourth pedigerous somites and urosomites free. Prosome 1.70 long. Genital somite ( Fig. 6 A, B), 0.28 × 0.28. Abdomen progressively narrowing posteriorly, composed of four free somites, 0.32 × 0.26, 0.34 × 0.25, 0.25 × 0.24, and 0.44 × 0.23, respectively. Caudal ramus ( Fig. 6 A) 5.33 times longer than wide, 0.54 × 0.10, with six setae.

Antennule, antenna, mandible, maxillule, and maxilla as in female. Maxilliped ( Fig. 6 C) 4-segmented; basal segment rod-like; second segment bearing single seta and patches of spinules; third segment small with two elements; terminal claw curved, bearing two basal elements and row of spinules on inner margin. Armature formula of legs 1 to 4 as in female. Leg 5 as in female. Leg 6 ( Fig. 6 B) represented by two simple setae on genital operculum.

Variability. Morphology of paratypes and other female specimens examined as in holotype. Measurements of the body parts of paratypes and other specimens (n = 11) as follows: body length 5.88–8.97 (7.39 ± 1.09); cephalosome length 0.58–0.94 (0.73 ± 0.09); cephalosome width 0.72–1.02 (0.84 ± 0.09); prosome length 1.90–2.89 (2.33 ± 0.34); genital somite length 0.42–0.55 (0.48 ± 0.04); genital somite width 0.58–0.86 (0.70 ± 0.09); first urosomite length 0.34–0.72 (0.55 ± 0.13); first urosomite width 0.43–0.62 (0.51 ± 0.07); second urosomite length 0.49–0.83 (0.68 ± 0.12); second urosomite width 0.45–0.63 (0.52 ± 0.05); third urosomite length 0.51–0.87 (0.68 ± 0.12); third urosomite width 0.42–0.62 (0.49 ± 0.06); anal somite length 0.91–1.49 (1.15 ± 0.21); anal somite width 0.33–0.52 (0.40 ± 0.07); caudal ramus length 0.87–1.58 (1.18 ± 0.26); caudal ramus width 0.12–0.22 (0.16 ± 0.03). Caudal ramus 5.95–9.32 (7.31 ± 0.93) times longer than wide.

The morphology of paratypes and other male specimens as in allotype. The measurements of the body parts of paratypes and other specimens (n = 3) are as follows: body length 2.88–6.32 (4.22 ± 1.84); cephalosome length 0.43–0.59 (0.52 ± 0.08); cephalosome width 0.44–0.85 (0.62 ± 0.21); prosome length 1.36–2.34 (1.70 ± 0.56); genital somite length 0.18–0.43 (0.28 ± 0.13); genital somite width 0.22–0.48 (0.34 ± 0.13); first urosomite length 0.18–0.52 (0.30 ± 0.19); first urosomite width 0.18–0.43 (0.30 ± 0.12); second urosomite length 0.25–0.54 (0.35 ± 0.17); second urosomite width 0.16–0.41 (0.28 ± 0.12); third urosomite length 0.17–0.49 (0.27 ± 0.19); third urosomite width 0.15–0.45 (0.28 ± 0.16); anal somite length 0.28–0.94 (0.52 ± 0.36); anal somite width 0.17–0.39 (0.27 ± 0.11); caudal ramus length 0.35–1.12 (0.69 ± 0.39); caudal ramus width 0.07–0.16 (0.11 ± 0.05). Caudal ramus 5.11–6.95 (5.85 ± 0.97) times longer than wide.

Remarks. Panaietis doraconis n. sp. differs from P. haliotis and P. malleolata in having legs 1 to 4 with spatulate spines on both rami in the female (vs. slender and pointed spines) (see Sars 1918, pl. CXII; Yamaguti 1936, figs 21–24). The new species is distinguished from P. yamagutii in having the following characters in both sexes: dorsal plate on first pedigerous somite lacking posterolateral lobes in both sexes (vs. with posterolateral lobes); leg 5 situated on lateral side of pedigerous somite with one elongate rod-like free exopod (vs. leg 5 with small free exopod situated on posteroventral side of pedigerous somite) (see Izawa 1976, figs 28, 37, 39, 50). Panaietis incamerata differs from P. doraconis n. sp. in having the following characters: presence of posterolateral lobes on first pedigerous somite in both sexes (vs. such lobes absent); genital somite bearing pair of bulbous swellings and pair of genital openings on ventral surface in female (vs. small lobes absent; genital opening on dorsal surface) (present study).

Attachment site. Pharynx and esophagus.

Etymology. The specific name of the new species, doraconis , refers to the elongate body of the new species which evokes a dragon.

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

Figures

FIGURE 4. Panaietis draconis n. sp., adult female, holotype NSMT – Cr 24622. A, habitus, dorsal; B, rostral area; C, genital aperture and leg 6, dorsal; D, right caudal ramus, dorsal; E, left antennule; F, right antenna, anterior; G, labrum, anterior. Scale bars: A, 1 mm; B, D, E, 200 µm; C, F, G, 50 µm.

FIGURE 5. Panaietis draconis n. sp., adult female, holotype NSMT – Cr 24622. A, right mandible, posterior; B, left maxillule, anterior; C, left maxilla, posterior; D, right maxilliped, anterior; E, left leg 1, anterior; F, left leg 2, anterior; G, right leg 3, anterior; H, right leg 4, anterior; I, left leg 5, dorsal. Scale bars: A, C, 40 µm; B, D, 20 µm; E – H, 100 µm; I, 200 µm.

FIGURE 6. Panaietis draconis n. sp., adult male, allotype NSMT – Cr 24623. A, habitus, dorsal; B, genital somite, ventral; C, left maxilliped, inner. Scale bars: A, 400 µm; B, 100 µm; C, 20 µm.