Eudorella parahirsuta Akiyama & Gamô, 2012, sp. nov.

Eudorella parahirsuta sp. nov.

(Figs. 32, 33)

Material examined. Holotype, ovigerous female, 5.3 mm, dissected (NSMT-Cr 22159), off Chiba, 34°42.35ˏN, 140°45.82ˏE – 34°41.22ˏN, 140°44.60ˏE, 2234–2240 m (KT-01-8, St. TK-4), 23 June 2001. Paratypes; 2 preparatory female, 5.2, 5.4 mm, dissected (NSMT-Cr 22160), KT-01-8, St. TK-4; 1 subadult male, 4.6 mm, dissected (NSMT-Cr 22161), Okinawa Trough, 28°46.17ˏN, 127°19.10ˏE – 28°46.95ˏN, 127°19.68ˏE, 974–997m (KT-04- 24, St. F2), 22 October, 2004; 1 subadult male, 4.8 mm (NSMT-Cr 22162), Okinawa Trough, 28°57.07ˏN, 127°46.51ˏE – 28°57.88ˏN, 127°47.11ˏE, 1094–1105 m, (KT-04-24, St. F3) 22 October, 2004; 1 ovigerous female (badly damaged), 1 preparatory female, 5.3 mm, dissected (NSMT-Cr 22163), off Shimokita, 41°04.5ˏN, 143°52.0ˏE – 41°04.5ˏN, 143°52.0ˏE, 3000m (KT 08-27, St. B16), 25 October, 2008.

Description. 2 ovigerous females (1 specimen badly damaged) and 3 preparatory females, 5.2–5.4 mm in length (Fig. 32). Body slender, integument weakly calcified, covered with fine setae (Fig. 32 A). Carapace length about 0.20–0.21 times total body length, 1.4–1.5 times greatest width, and 1.4–1.7 times the depth; upper front corner vaulted, with bundle of long setae; frontal margin serrated, not reaching near siphon; antennal notch with 1–3 teeth on lower end; anterolateral corner round; inferior margin curved, weakly serrated. Pereon 1.1 times carapace. Pleon 0.55–0.56 times total body length; dorso-posterior end of 5th pleonite without long setae.

Antenna 1 (Fig. 32 D) 1st article of peduncle with 2–4 plumose setae on lower margin and 5–6 plumose or simple setae on inner margin; 3rd article of peduncle shorter than 2nd, with 4–5 plumose and 1 simple seta on outer margin, with 5–7 plumose setae on inner margin and with 1–2 simple setae on frontal margin; main flagellum shorter than or subequal to 2nd article of peduncle, with 3–5 simple setae on outer margin; accessory flagellum shorter than 1st article of main flagellum. Antenna 2 with no setae on lower margin (Fig. 3 E). Right and left mandibles, maxilla 1 and maxilla 2 normal (Fig. 32 F–H). Maxilliped 1 (Fig. 32 I) with 3–5 small branchial lobules. Maxilliped 2 (Fig. 32 J) basis shorter than combined length of succeeding 3 articles, with 1 seta on inner margin (arrowhead). Maxilliped 3 (Fig. 32 K) basis length 0.9–1.0 times length of distal articles together, with 6–10 plumose setae on inner margin and 3–5 setae on ventral surface; ischium with a spine on inner margin; carpus with 9– 12 plumose setae on inner margin.

Pereopod 1 (Fig. 32 L) basis length 0.6 times distal articles together, with several simple setae on outer margin; propodus 1.3 times carpus and 1.9–2.1 times dactylus. Pereopod 2 (Fig. 32 M) basis length 0.6–0.7 times distal articles together; carpus extremely elongate, 1.9–2.1 times merus and 1.8–1.9 times combined length of propodus and dactylus; propodus short, with shallow notch on distal corner; dactylus not swollen, with 10–11 stiff setae. Pereopod 3 (Fig. 32 N) basis length 1.8–2.1 times remaining distal articles. Pereopod 4 (Fig. 32 O) basis length 1.5–1.9 times distal articles together. Pereopod 5 (Fig. 32 P) basis length 1.1–1.6 times distal articles together.

Uropod (Fig. 32 Q) peduncle length 1.3 times length of pleonite 6, 0.96–1.06 times exopod and 1.14–1.25 times 1st article of endopod, with 4–6 spiniform setae on inner margin. Exopod 1.14–1.19 times 1st article of endopod, with 7–9 plumose or simple setae on inner margin and apical end, 3–5 simple setae on dorsal surface, and 3–5 simple setae on ventral surface. Endopod 1st article 3.1–3.7 times 2nd, with 7–8 spiniform setae on inner margin and 3–4 short simple setae on outer margin; 2nd article with 2–3 spiniform setae on inner margin; terminal seta longer than 2nd article, defined at base.

Subadult male, 4.6 mm in length (Fig. 33). Carapace 0.22 times as long as total body length, 1.5 times the greatest width and 1.5 times depth; upper front corner with a bundle of setae projecting forward and upward; frontal margin prominently serrated; antennal notch absent; inferior margin with 9, 14 teeth. Pereon length 1.0 times carapace length. Pleon length 0.57 times total body length, with 2 pairs of undeveloped pleopods; dorso-posterior end of 5th pleonite with no long setae.

Antenna 1 (Fig. 33 D) 1st article of peduncle with 3 and 4 plumose setae on lower and inner margin respectively; 3rd article of peduncle shorter than 2nd, with 4 plumose setae and 1 simple seta on outer margin, with 6 plumose setae on inner margin, and 2 simple setae on frontal margin. Main flagellum subequal to 2nd article of peduncle, with 4 simple setae on outer margin of 1st article. Accessory flagellum slightly shorter than 1st article of main flagellum. Antenna 2 (Fig. 33 E) with elongate flagellum; peduncle with 3 plumose setae. Maxilliped 3 (Fig. 33 F), basis 1.0 times distal articles, with 8 and 5 plumose setae on inner margin and ventral surface, respectively; ischium with 1 spine on inner margin.

Pereopod 1 (Fig. 33 G) basis length 0.65 times length of distal articles combined; propodus 1.4 times merus and 1.9 times dactylus. Pereopod 2 (Fig. 33 H) basis length 0.9 times distal articles combined; carpus 2.1 times merus and 1.6 times combined length of propodus and dactylus; dactylus with 10 stiff setae projecting radially. Pereopod 3 and 4 (Fig. 33 I, J) basis lengths 2.6, 2.2 times distal articles together, respectively, broad at base. Pereopod 5 (Fig. 33 K) basis length 1.5 times distal articles combined. Undeveloped pleopod (Fig. 33 L) normal.

Uropod (Fig. 33 M) peduncle length 1.4 times pleonite 6, 0.97 times exopod, and 1.13 times 1st article of endopod, with 5 spiniform setae on inner margin. Exopod length 1.17 times the 1st article of endopod, with 8 plumose or simple setae on inner margin and apical end, 4 simple setae on dorsal surface, and 4 or 5 simple setae on ventral surface. Length of 1st article of endopod 3.3 times length of 2nd, with 9 spiniform setae on inner margin and 3 simple setae on outer margin; 2nd article with 3 minute spiniform setae on inner margin; robust terminal setae longer than 2nd article, defined at base.

Etymology. This species name refers to the similarity in morphology with E. hirsuta Sars, 1869.

Remarks. Females of E. parahirsuta sp. nov. are closely similar to E. hirsuta Sars, 1869, found in the Northeast Atlantic, 207–2524 m, especially in the shape of the carapace and pereopod 2 with an extremely elongate carpus. However, they can be distinguished as follows. (1) The serrated frontal margin of the carapace does not reach near the siphon (reaching near the siphon in E. hirsuta), (2) The propodus of pereopod 1 is much longer than the carpus (subequal in length in E. hirsuta) and twice as long the dactylus (only about 1.5 times in E. hirsuta). In the subadult male, the frontal margin of the carapace in E. parahirsuta is markedly serrated (not serrated in E. hirsuta).

Distribution. Pacific coast of northern Honshu, off Boso Peninsula, and Okinawa Trough, 974–3000 m.