Nagasawanus snufkini, Uyeno, Daisuke, 2015

Uyeno, Daisuke, 2015, Systematic revision of the pennellid genus Creopelates Shiino, 1958 (Copepoda: Siphonostomatoida) and the proposal of a new genus, Zootaxa 3904 (3), pp. 359-386 : 379-380

Nagasawanus snufkini n. sp.

New Japanese name: Shin-no-wakizashi ( Figs 11 B, C, 14, 15)

Type material. Holotype: postmetamorphic adult female (NSMT-Cr 23847) (dissected), ex Trimma tevegae Cohen & Davis ( Perciformes : Gobiidae ), off Oura Bay (26°32'N, 128°3'E), Okinawa-jima Island, Ryukyu Islands, North Pacific Ocean, Japan, 10 m depth, 28 January 2014, leg. D. Uyeno, S. Nishihira, and M. Arai. Paratype: 1 postmetamorphic adult female (NSMT-Cr 23848), ex T. tevegae , off Oura Bay (26°32'N, 128°3'E), Okinawa-jima Island, Ryukyu Islands, North Pacific Ocean, Japan, 13 m depth, 19 February 2012, leg. D. Uyeno and S. Nishihira; 1 postmetamorphic adult female (NSMT-Cr 23849) (dissected), ex T. tevegae , off Oura Bay (26°32'N, 128°3'E), Okinawa-jima Island, Ryukyu Islands, North Pacific Ocean, Japan, 14 m depth, 20 October 2013, leg. D. Uyeno and S. Nishihira; 1 postmetamorphic adult female (RUMF-ZC-3679), ex T. tevegae , off Oura Bay (26°32'N, 128°3'E), Okinawa-jima Island, Ryukyu Islands, North Pacific Ocean, Japan, 14 m depth, 20 October 2013, leg. D. Uyeno and S. Nishihira.

Description of postmetamorphic adult female. Body ( Fig. 14 A) 6.39 long, comprising cephalothorax, neck region and trunk; junction of neck and trunk curved. Cephalothorax ( Fig. 14 A–D) longer than wide 0.53 × 0.41, bearing paired rounded antennary process with small additional rounded protrusions and posterolateral lobes; rostrum ( Fig. 14 E) narrow, with curved frontal margin. Neck region ( Fig. 14 A) curved in anterior ⅓, narrowing slightly towards trunk; second and third pedigers clearly segmented ( Fig.14 B, D). Trunk ( Fig. 14 A, F) pyriform, longer than wide 2.80 × 0.81, with anterior end narrowing towards neck region. Abdomen conical, bearing median depression, located between oviducal pores ( Fig. 14 A, F, G). Egg-sac uniseriate, curved in single plane ( Fig. 14 A).

Antennule ( Fig. 14 H) unsegmented, bearing 21 setae on anterior margin: distal tip 11 setae distally, 2 of which sharing common base, and 1 aesthetasc. Antenna ( Fig. 15 A) 3-segmented, chelate, typical pennellid; proximal segment unarmed; middle segment bearing one pointed protrusion on inner medial margin, terminal segment clawlike bearing small basal element on posterior surface. Mouth tube, maxillule, and maxilla located near base of antenna on anterior part of ventral surface of cephalothorax. Maxillule ( Fig. 15 B) bilobate, composed of knob-like lobes; inner lobe bearing one seta; outer lobe bearing two setae. Maxilla ( Fig. 15 C) 2-segmented; proximal segment bearing single subterminal pointed long process; terminal segment forming elongate claw with one row of teeth-like processes along posterior margin. Maxilliped absent.

Legs 1 and 2 ( Fig. 15 E) biramous. Legs 3 and 4 ( Fig. 15 G) uniramous. Legs 1 to 4 evenly arrayed along posterior part of cephalothorax to neck region ( Fig. 14 C). Armature formula of legs as follows:

Protopod Exopod Endopod Leg 1 broken broken broken Leg 2 1–0 1–1; 7 0–1; 7 Leg 3 broken broken broken Leg 4 1–0 broken Absent Protopods of legs 1 to 4 connected to respective intercoxal sclerites ( Figs 14 C, 15E, G). Attachment site. The cephalothorax and neck of the copepod were embedded in the musculature of the host’s trunk posterior to the base of the pectoral fin and attached to the vertebrae, while its trunk and egg sacs remained external the fish’s body wall ( Fig. 11 B, C).

Variability of female morphology. The morphology of the female paratypes is as in the holotype. Armature formula of legs 1 and 3 of paratypes ( Fig. 15 D, F) as follows:

Protopod Exopod Endopod Leg 1 1–1 1–1; 7 0–1; 7

Leg 3 1–0 0–0; 6 absent Measurements of paratypes as follows (n = 3): body length 6.18–7.25 mm (6.84 ± 0.58); cephalothorax length 0.44–0.65 (0.56 ± 0.11); cephalothorax width 0.33–0.35 (0.34 ± 0.02); trunk length 2.62–2.90 (2.76 ± 0.20); trunk width 0.73–0.93 (0.83 ± 0.14).

Remarks. Nagasawanus snufkini n. sp. clearly differs from its congener N. akinohama n. sp. by the following character states: cephalothorax connecting along linear axis to second pedigerous somite (vs. connecting via 90o flexure to second pedigerous somite); antennary processes with a small additional rounded protrusion (vs. with four additional protrusions); neck region without constricted, narrowed section (vs. with posterior constriction); maxilla with terminal segment with a serrated margin (vs. with a smooth margin) in postmetamorphic adult female.

Etymology. The specific name of the new species, snufkini , refers to the nickname of Mr. Shin Nishihira, the founder of the Diving Team Snuck Snufkin, who is the best explorer of Oura Bay, Okinawa-jima Island, Japan.

Figures

FIGURE 11. Postmetamorphic adult females of Nagasawanus akinohama n. gen. et n. sp. (A) and N. snufkini n. sp. (B, C) attached to their hosts. A, a specimen of Trimma grammistes (Tomiyama) infected by the paratype female (NSMT-Cr 23845), c = a female specimen of Cardiodectes asper Uyeno & Nagasawa, 2010, n = paratype female of N. akinohama n. gen. et n. sp.; B, a specimen of Trimma tevegae Cohen & Davis infected by a specimen of N. snufkini. C, coloration in life of a specimen attached to host’s body. Scale bars: A, C, 2 mm; B, 5 mm.

FIGURE 14. Nagasawanus snufkini n. sp., postmetamorphic adult female, holotype, NSMT-Cr 23847. A, habitus; B, cephalothorax and anterior end of neck region, dorsal; C, same, ventral; D, same, lateral; E, anterior part of cephalothorax with rostrum; F, trunk, ventral; G, posterior part of trunk, ventral; H, left antennule, anterior. Scale bars: A, 2000 µm; B – D, 300 µm; E, 100 µm; F, 1000 µm; G, 200 µm; H, 30 µm.

FIGURE 15. Nagasawanus snufkini n. sp., postmetamorphic adult female, holotype, NSMT-Cr 23847 (A – C, E, G), paratype, NSMT-Cr 23849 (D, F). A, right antenna, anterior; B, left maxillule; C, right maxilla, anterior; D, right leg 1 with intercoxal sclerite, anterior; E, right leg 2 with intercoxal sclerite, anterior; F, right leg 3 with intercoxal sclerite, anterior; G, left leg 4 with intercoxal sclerite, anterior. Scale bars: A, D – F, 50 µm; B, C, G, 30 µm.