Panaietis flavellata, Uyeno, 2019

Uyeno, Daisuke, 2019, Two new species of Panaietis (Copepoda: Cyclopoida: Anthessiidae) associated with vetigastropods (Gastropoda) in coastal waters of southern Japan, Zootaxa 4652 (1), pp. 135-144 : 140-142

Panaietis flavellata sp. nov.

( Figs 4 –6)

urn:lsid:zoobank.org:act:8C79DBCB-1B41-4BDA-8985-9B8DEDE1B5B3

Type material. Holotype: adult female (NSMT-Cr 26681), ex Angaria neglecta Poppe & Goto (Vetigastropoda: Trochida: Angariidae ), Akamizu (31°15'N, 130°15'E), off Satsuma Peninsula, Kagoshima , the East China Sea, Japan, 4 May 2016, leg. D. Uyeno . Paratypes: 1 adult female (NSMT-Cr 26682), ex A. neglecta, Akamizu (31°15'N, 130°15'E), off Satsuma Peninsula, Kagoshima, the East China Sea, Japan, 3 August 2016, leg. D. Uyeno ; 1 adult female (NSMT-Cr 26683), ex A. neglecta , off Nomaike (31°25'N, 130°8'E), Satsuma Peninsula, Kagoshima, the East China Sea, Japan, 16 December 2018, leg. D. Uyeno ; adult female (NSMT-Cr 26684), ex A. neglecta , off Cape Bonomisaki (31°15'N, 130°13'E), Satsuma Peninsula, Kagoshima, the East China Sea, Japan, 2 January 2019, leg. D. Uyeno and H. Uyeno

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Holotype adult female. Body ( Fig. 4A ) cyclopiform, 3.01 long; external segmentation distinct. Cephalosome incompletely separated from first pediger, wider than long, 0.53 × 0.77. First to fourth pedigers and six urosomites free; third and fourth pedigers wider than cephalosome. Prosome 1.52 long. Genital somite bearing pair of lateral lobes ( Fig. 4A, B ), 0.26 × 1.01; paired genital openings situated on dorsal side. Abdomen composed of four free somites, 0.19 × 0.48, 0.18 × 0.46, 0.12 × 0.39, and 0.35 × 0.37, respectively. Caudal ramus ( Fig. 4A, C ) 2.40 times longer than wide, 0.43 × 0.18, with six minute setae.

Rostral area triangular without distinct apex. Antennule ( Fig. 4D ) 7-segmented; armature formula 6, 16, 4, 4, 4 + 1 aesthetasc, 2 + 1 aesthetasc, 7 + 1 aesthetasc; all setae simple. Antenna ( Fig. 4E ) 3-segmented, composed of coxobasis and 2-segmented endopod: coxobasis large, bearing simple distal seta; first endopodal segment bearing well developed conical protrusion with simple apical seta; second endopodal segment bearing four setae on inner margin and terminal claw, three claw-like spines, and three long distal setae on distal margin. Labrum ( Fig. 4F ) broad, bilobed. Mandible ( Fig. 4G ) bearing single lash-like seta with row of fine spinules on one of margin and apical serrated lash with two basal hyaline teeth. Maxillule ( Fig. 4H ) represented by unsegmented lobe bearing inner elongate protrusion tipped with minute element, outer basal seta, and three short distal elements. Maxilla ( Fig. 4I ) 2-segmented; proximal segment rod-like, unarmed; distal segment bearing five sharp teeth and two basal setae. Maxilliped ( Fig. 4J ) 2-segmented, composed of unarmed stout proximal portion and distal portion.

Legs 1 to 4 ( Fig. 5 A–D) biramous, bearing 3-segmented rami. Leg armature formula as follows:

Intercoxal sclerites ( Fig. 5 A–D) of legs 1 to 4 unarmed. All spines spatulate. Proximal and middle endopodal segments of legs 1 to 4 bearing pointed protrusions on outer margin. Leg 5 ( Fig. 5E ) 2-segmented, situated on posteroventral surface of pediger ( Fig. 4A ); proximal segment incompletely fused to fifth pediger with small simple seta on outer margin; distal segment elongate bearing three spatulate spines and single seta. Leg 6 represented by simple seta at genital opening.

Male. Unknown.

Variability. The morphology of the female paratypes as in holotype. The measurements of the body parts of paratypes (n = 3) are as follows: body length 2.57–3.17 (2.83 ± 0.37); cephalosome length 0.48–0.55 (0.51 ± 0.05); cephalosome width 0.64–0.79 (0.72 ± 0.11); prosome length 1.37–1.65 (1.51 ± 0.20); genital somite length 0.21–0.26 (0.24 ± 0.04); genital somite width 0.56–0.64 (0.60 ± 0.06); first urosomite length 0.13–0.21 (0.17 ± 0.06); first urosomite width 0.41–0.46 (0.43 ± 0.05); second urosomite length 0.13–0.25 (0.19 ± 0.08); second urosomite width 0.40–0.44 (0.42 ± 0.03); third urosomite length 0.14–0.20 (0.17 ± 0.05); third urosomite width 0.36–0.36 (0.36 ± 0.00); anal somite length 0.27–0.30 (0.28 ± 0.02); anal somite width 0.34–0.37 (0.35 ± 0.02); caudal ramus length 0.43–0.45 (0.44 ± 0.01); caudal ramus width 0.14–0.16 (0.15 ± 0.01). Caudal ramus 2.65–3.13 (2.89 ± 0.34) times longer than wide.

Remarks. Of all its congeners, Panaietis flavellata sp. nov. shares leg 5 situated on the posteroventral side of the fifth pediger only with P. yamagutii ( Yamaguti 1936; Izawa 1976; Ho 1981; Kim 1998). The new species clearly differs from P. yamagutii by following characters: inner margin of second segment of antenna greatly protruded at base of small seta (vs. not protruded); leg 3 endopod bearing single seta on third endopodal segment (vs. two setae) ( Yamaguti 1936; Izawa 1976).

Attachment site. Mouth cavity to esophagus.

Etymology. The specific name of the new species, flavellata , refers to the spatulate and fan shaped spines on legs.

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

Figures

FIGURE 4. Panaietis flavellata sp. nov., adult female, holotype NSMT-Cr 26681. A, habitus, dorsal; B, left genital aperture and leg 6, dorsal; C, right caudal ramus, dorsal; D, left antennule, posterior; E, left antenna, anterior; F, labrum; G, left mandible, posterior; H, left maxillule, anterior; I, right maxilla, anterior; J, right maxilliped, anterior. Scale bars:A, 0.4 mm; B–D, 0.1 mm; E, F, 0.05 mm; G, H, 0.03 mm; I, 0.04 mm. J, 0.02 mm.

FIGURE 5. Panaietis flavellata sp. nov., adult female, holotype NSMT-Cr 26681. A, right leg 1, anterior; B, right leg 2, anterior; C, right leg 3, anterior; D, right leg 4, anterior; E, left leg 5, anterior. Scale bars: A–D, 0.1 mm; E, 0.05 mm.