Eudorella bathyalis Vassilenko & Tzareva, 2004

Akiyama, Tadashi & Gamô, Sigeo, 2012, The cumacean Genus Eudorella (Crustacea: Peracarida) from Japanese Waters, Northwest Pacific, and E. suluensis sp. nov. from the Sulu Sea, Indo-West Pacific, Zootaxa 3319, pp. 1-56 : 11-15

Eudorella bathyalis Vassilenko & Tzareva, 2004

( Figs. 7–9 )

Eudorella bathyalis Vassilenko & Tzareva, 2004: 9 –13, figs. 5, 6. Eudorella ?hispida Akiyama 2009: 486.

Material examined. 1 ovigerous female carrying 52 embryos, 9.2 mm, 1 subadult male, 8.0 mm, 1 preparatory female (badly damaged), 2 juveniles (NSMT-Cr 22101), off Kushiro, Hokkaido, 42°23.83ˏN 145°31.06ˏE – 42°22.00ˏN, 145°27.70ˏE, 3108–3265 m (KH-01-2, St. XR-5), 16 September, 2001; 1 preparatory female, 7.2 mm (NSMT-Cr 22102), off Kushiro, 42°28ˏN,144°15ˏE – 42°27ˏN, 144°13ˏE, 965–982 m (KH-01-2, St. XR-2), 15 September 2001; 4 preparatory females, 5.6–6.8 mm, 5 young females, 4 young males, 1 manca (NSMT-Cr 22103), Hiroo Canyon, off Hokkaido, 42°11ˏN, 144°11ˏE–42°11ˏN, 144°12ˏE, 1134–1219 m (KH-01-2, St. KC-0), 18 September, 2001; 2 juveniles (NSMT-Cr 22104), south of Hokkaido, 42°11.91ˏN, 141°44.87ˏE – 42°11.17ˏN, 141°45.23ˏE, 771 m (KT-05-6, St. BT-4), 6 April 2005; 6 ovigerous females, 7.9–8.5 mm (NSMT-Cr 22105), off Todogasaki, northern Honshu, 39°31ˏN, 142°32ˏE – 39°32ˏN, 142°34ˏE, 1002–1069 m (KH-01-2, St. TD-2), 25 September, 2001; 1 adult female, 7.9 mm, 5 juveniles, 5 manca larvae (NSMT-Cr 22106), off Todogasaki, 39°27.08ˏN, 143°37.79ˏE–39°29.15ˏN, 143°38.52ˏE, 3110–3290 m (KH-01-2, St. TD-4), 26 September 2001; 2 juveniles (NSMT-Cr 22107), 33°38.2ˏN, 136°30.4ˏE–33°38.2ˏN, 136°34.6ˏE, 2072–2075 m (KT-99-18, St. BT-6), 20 December 1999; 1 preparatory female, 6.5 mm, 2 juveniles (NSMT-Cr 22108), 33°50.0 ˏN, 136°32.6ˏE – 33°50.0ˏN, 136°28.9ˏE, 1947–2023 m (KT-99-18, St. BT-9), 20 December 1999; 1 ovigerous female, 1 adult male (NSMT-Cr 22109), Okinawa Trough, 28°57.07ˏN, 127°46.51ˏE – 28°46.95ˏN, 127°47.11ˏE, 1094–1105 m (KT- 04-24, St. F-3), 22 October 2004; 1 subadult male (NSMT-Cr 22110), Okinawa Trough, 29°38.4ˏN, 127°36.0ˏE – 29°39.1ˏN, 127°35.9ˏE, 524–575 m (KT-04-23, St. D1-aˏ), 12 October, 2004.

Description. Ovigerous and preparatory females from northern Japan, 5.6–10.1 mm ( Figs. 7 , 8 ). Body slender, well or very weakly calcified, covered with numerous short bristles. Carapace length 0.17–0.20 times total body length, 1.0–1.4 times width, latter being 0.9–1.3 times depth; upper front corner with a group of setae projecting forward; row of 3–5 stiff setae on each side; frontal margin smooth, upper and lower margin of antennal notch with 3–5 and 2–3 teeth respectively ( Fig. 7 C); inferior margin armed with prominent or moderate teeth. Pereon length 1.2–1.5 times carapace. Pleon 0.54–0.60 times total body length; dorso-posterior margin of pleonite 5 with no long setae.

Antenna 1 ( Fig. 7 D) 1st article of peduncle with several plumose setae and numerous fine bristles on ventral surface; 3rd article of peduncle shorter than 2nd, with 4–7 plumose setae and 1 simple seta on outer margin and 4– 8 plumose setae on inner margin. Main flagellum subequal in length to 2nd article of peduncle; 1st article about 3 times combined length of distal 2 articles and with 3–6 simple setae on outer margin. Accessory flagellum much shorter than 1st article of main flagellum. Antenna 2 ( Fig. 7 E) with 3 plumose setae on outer margin. Left and right mandible ( Fig. 7 F) with lacinia mobilis and minute spiniform seta (arrow head) respectively, in addition to 2 simple setae, respectively. Maxilliped 1 ( Fig. 7 I) with 8–12 branchial lobules. Maxilliped 2 ( Fig. 7 J) basis length subequal to combined length of succeeding 3 articles, with no setae on inner or ventral margin. Maxilliped 3 ( Fig. 7 K) basis 1.0–1.3 times remaining distal articles, with 7–11 and 4–7 plumose setae on inner margin and ventral surface, respectively; ischium with a prominent spine on inner margin; carpus with 6–10 plumose setae on inner margin.

Pereopod 1 ( Fig. 7 L) basis length 0.6–0.7 times distal articles together, with a row of plumose setae on both inner and outer margin, and with a patch of setae on ventral surface. Pereopod 2 ( Fig. 8 A) basis 0.6–0.7 times distal articles together, plumose setae on inner margin; dactylus slightly swollen or not distally, with 12–19 apical setae projecting radially; carpus 1.3–1.65 times merus; propodus with deep notch for nearly entire length of article. Pereopod 3 ( Fig. 8 B) basis 1.4–1.9 times distal articles together; distal half of carpus with 4 stiff setae. Pereopod 4 ( Fig. 8 C) basis 1.4–2.0 times distal articles together, with several long simple setae; distal half of carpus with 4 simple setae. Pereopod 5 ( Fig. 8 D) basis 1.05–1.5 times remaining distal articles; distal portion of carpus with 4 long setae.

Uropod ( Fig. 8 E) peduncle length 1.40–1.72 times pleonite 6 length, 1.03–1.26 times exopod, 0.89–0.99 times endopod, with 3–12 spiniform setae on inner margin; exopod length 0.94–1.24 times length of basal article of endopod, with 9–12 plumose setae on inner margin and distal end, and with 4–6 setae on dorsal surface. Endopod 1st article 3.7–4.8 times 1st article, with 9–14 unequal serrated spiniform setae on inner margin; 2nd article 2–5 spiniform setae on inner margin; terminal spiniform setae robust, defined at base.

Adult male from Okinawa Trough, southern Japan, 5.9 mm ( Fig. 9 ). Body slender, integument well calcified, with few hairs. Carapace length 0.21 times total body length, 1.3 times greatest width and 1.4 times depth; row of stiff setae absent from both sides; frontal margin with 4 teeth ( Fig. 9 C); antennal notch obsolete; inferior margin with 4–5 teeth on anterior portion. Pereon length 1.1 times carapace length. Pleon length 0.55 times total body length, with 2 pairs of pleopods. Dorso-posterior margin of 5th pleonite without long seta.

Antenna 1 ( Fig. 9 D), 1st article of peduncle with 3 setae on ventral and inner margins. 3rd peduncular article shorter than 2nd, with 5 plumose setae and 1 simple seta on outer margin, 6 plumose setae on inner margin, and 2 plumose setae on frontal margin. Main flagellum shorter than 2nd article of peduncle, 4-articulate; 1st article as long as 2nd, with simple setae on outer distal corner and 10 aesthetascs on proximal region; 2nd article with 3 simple setae on outer margin; combined length of 3rd and 4th articles shorter than 1st or 2nd; 4th article minute, with 1 aesthetasc. Accessory flagellum reaching middle portion of 2nd article of main flagellum. Antenna 2 ( Fig. 9 E) with 4 plumose setae on basal region of peduncle; distal portion of flagellum lost. Maxilliped 3 ( Fig. 9 F) basis length 1.4 times distal articles together, 8 plumose setae on inner margin and 3 plumose and 2 simple setae on ventral surface; ischium with a spine on inner margin; carpus with 8 plumose setae on inner margin.

Pereopod 1 ( Fig. 9 G) basis length 0.8 times distal articles together, with 14 setae on inner margin, 8 setae on outer margin, and 10 setae on ventral surface; propodus 1.5 times carpus and 2.3 times dactylus. Pereopod 2 ( Fig. 9 H) basis 0.9 times distal articles together, with 8 plumose setae on inner margin; carpus 1.5 times merus and 1.0 times combined length of propodus and dactylus; propodus with deep notch on distal corner, almost reaching basal end of article; dactylus slightly swollen distally, with 15 setae projecting radially. Pereopod 3 ( Fig. 9 I) basis length 2.7 times distal articles together, with 10 plumose setae on inner margin. Pereopod 4 ( Fig. 9 J), basis 2.4 times distal articles together, with 4 plumose setae. Pereopod 5 ( Fig. 9 K) basis 1.6 times distal articles together, with 6 long plumose setae. Pleopod 1 normal ( Fig. 9 K).

Uropod ( Fig. 9 M) peduncle length 1.44 times as long as pleonite 6, 0.99 times exopod, 0.76 times endopod, with 5 spiniform setae and 5 plumose setae on inner margin; exopod 0.94 times basal article of endopod, with 12 plumose setae on inner margin and apical end, with 8 simple setae on dorsal surface, and 3 short setae on ventral surface. Length of 1st article of endopod 4.7 times 2nd, with 19 spiniform setae and 6 plumose setae on inner margin and 7 simple setae on outer margin; 2nd article with 4 or 5 spiniform setae on inner margin; robust terminal seta shorter than 2nd article, defined at base.

Remarks. The morphology of the specimens corresponds with the description of specimens from the Sea of Japan recorded by Vassilenko & Tzareva (2004). The Japanese specimens are characterized by a row of simple setae on each side of the carapace, which were also observed in Eudorella orientalis sp. nov., E. breviflagella sp. nov. from southern Japan, E. setoensis Akiyama & Gamô, 2006 from the Seto Inland Sea of Japan, and E. fusafusa sp. nov., from northern Japan. Female specimens of E. bathyalis are distinguished from those of the latter four species by combination of (1) accessory flagellum of antenna 1 much shorter than basal article of main flagellum (slightly shorter or subequal in the latter 4 species), (2) carpus of pereopod 2 much longer than merus (subequal or slightly longer in the latter four species), (3) 1st article of uropod endopod 4–5 times as long as the 2nd article (3 times or less in E.orientalis , E. breviflagella and E. setoensis ).

Distribution. Sea of Japan, Pacific coast of Japan, Okinawa Trough, East China Sea, 524–3290 m.

Figures

FIGURE 7. Eudorella bathyalis Vassilenko and Tzareva, 2004, ovigerous female. A, body, lateral view; B, anterior portion of body, from above; C, anterior portion of carapace; D, antenna 1; E, antenna 2; F, mandibles; G, maxilla 1; H, maxilla 2; I – K, maxillipeds 1 – 3; L, pereopod 1.

FIGURE 8. Eudorella bathyalis Vassilenko and Tzareva, 2004, ovigerous female. A – D, pereopods 2 – 5; E, uropod with pleonite 6.

FIGURE 9. Eudorella bathyalis Vassilenko and Tzareva, 2004, adult male. A, body, lateral view; B, anterior portion of body, from above; C, frontal margin of carapace; D, antenna 1; E, antenna 2; F, maxillipeds 3; G – K, pereopods 1 – 5; L, pleopod 1; M, urood with pleonite 6.