Eudorella haradai, Akiyama, Tadashi & Gamô, Sigeo, 2012

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 : 34-38

Eudorella haradai sp. nov.

( Figs. 23–25 )

Material examined. Holotype, ovigerous female carrying 7 spherical embryos, 4.3 mm, dissected (NSMT-Cr 22134), off Chiba, 34º43.38ˏN, 140°46.67ˏE – 34°41.22ˏN, 140°44.60ˏE, 2221–2240 m (KT-01-8, Station TK-4), 23 June 2001. Paratypes; subadult male, 5.0 mm, dissected, 1 preparatory female, 4.8 mm, dissected (NSMT-Cr 22135), Kumano Basin, 33º42.53ˏN, 136°43.32ˏE – 33°43.28ˏN, 136°44.72ˏE, 1982–2012 m, 1 May, 2004 (KT- 04-6, St. KN-8-1); 1 subadult male, 5.4 mm, dissected (NSMT-Cr 22136), off Kushiro, 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 females, damaged during collection, dissected (NSMT-Cr 22137), off Shimokita Peninsula, 41°04.5ˏN, 143°52.0ˏE – 41°04.5ˏN, 143°520ˏE, 3000 m (KT-08-27, St. B16), 25 October 2008.

Description. Females ( Figs. 23 , 24 ). Body slender; integument moderately calcified, with few setae. Carapace length 0.21 times total body length, 1.3–1.4 times greatest width and 1.2–1.3 times the depth; upper front corner with sparse short setae projecting upward and forward ( Fig. 23 C); frontal margin not serrated; antennal notch with 2 teeth each on upper and lower ends; anterolateral angle with tooth projecting forward, succeeded by 12 small teeth on inferior margin. Pereon length 1.1–1.2 times that of carapace. Pleon 0.56 or 0.57 times total body length; dorso-posterior margin of 5th segment with a pair of long setae exceeding uropods in length.

Antenna 1 ( Fig. 23 D) 3rd article of peduncle and main flagellum subequal in length to 2nd, with 2–4 plumose and 1–2 simple setae on outer margin, and with 5 plumose setae on inner margin; 1st article of peduncle with 2–3 setae on inner margin and with no setae on lower margin; main flagellum longer than 2nd article of peduncle, with 2–3 simple setae on outer margin. Accessory flagellum shorter than 1st article of main flagellum. Antenna 2 ( Fig. 23 E) with no setae on lower margin. Mandibles ( Fig. 23 F): left mandible with tridentate lacinia mobilis; right mandible with sharply pointed spiniform seta distally. Maxilla 1 and maxilla 2 normal ( Fig. 23 G, H). Maxilliped 1 with 3–4 small branchial lobules ( Fig. 23 I). Maxilliped 2 ( Fig. 23 J, K) basis shorter than combined length of ischium, merus and carpus, with several setae on inner margin. Maxilliped 3 ( Fig. 23 L) basis subequal to length of distal articles together, with 4–9 and 5–7 setae on inner margin and ventral surface, respectively; carpus with 8–9 plumose setae on inner margin.

Pereopod 1 ( Fig. 24 A) basis 0.7 times distal articles together, with 4 and 3–4 plumose setae on inner and outer margin respectively; propodus 1.0–1.1 times carpus and 1.4 or 1.8 times dactylus. Pereopod 2 ( Fig. 24 B) basis length 0.8–0.9 times length of remaining distal articles; carpus 1.3–1.5 times merus and 0.8–0.9 times combined length of propodus and dactylus; propodus with a notch on distal corner, reaching middle portion of article; dactylus not swollen distally, with 10 or 11 stiff setae projecting radially. Pereopods 3, 4 and 5 ( Fig. 24 C–E) basis lengths 1.6–2.0, 1.3–1.6 and 1.2–1.3 times distal articles together respectively.

Uropod ( Fig. 24 F). Peduncle length 1.4–1.5 times length of pleonite 6, 0.84–0.93 times exopod, 0.86–0.97 times 1st article of endopod; with 3–4 spiniform setae on its inner margin; exopod 1.0–1.1 times 1st article of peduncle, with 6–9 setae on inner margin and distal end, 4–5 setae on dorsal surface and 3–4 setae on ventral surface. Endopod 1st article 3.6–3.7 times 2nd article, with 8–10 spiniform setae on inner margin and 3 setae on outer margin; 2nd article with 4 spiniform setae on inner margin and a long, robust terminal seta.

2 subadult males ( Fig. 25 ). Carapace length 0.20, 0.22 times total body length, 1.44 times the greatest width and 1.29 times depth; upper front corner with a bundle of short setae ( Fig. 25 C); lower portion of frontal margin with several teeth directed upward and downward; antennal notch absent; inferior margin with 14–17 teeth, foremost one prominent, directed forward. Pereon length 1.0, 1.2 times carapace length. Pleon 0.56, 0.57 times total body length; 2 long setae on dorso-posterior end of 5th pleonite lost during collection, only sockets present.

Antenna 1 ( Fig. 25 D) 1st article of peduncle with 0 and 1–4 setae on lower and inner margin respectively; 3rd article of peduncle shorter than 2nd, with 2–4 and 5 plumose setae on outer and inner margin, respectively. Main flagellum length subequal to 2nd article of peduncle; 1st article with 2 or 3 simple setae on outer margin; accessory flagellum shorter than 1st article of peduncle. Antenna 2 ( Fig. 25 E) with 3 plumose setae on proximal region of peduncle. Maxilliped 3 ( Fig. 25 F) basis 1.2 times distal articles together, with 4or 9 plumose setae on inner margin and 5or 7 plumose setae on ventral surface.

Pereopod 1 ( Fig. 25 G) basis length 0.7, 0.8 times distal articles together; propodus 1.3, 1.4 times carpus and 1.6, 2.0 times dactylus. Pereopod 2 ( Fig. 25 H) basis 1.0 or 1.1 times distal articles together; carpus 1.3 times merus and 0.8 times combined length of propodus and dactylus; dactylus with 10 or 11 stiff setae. Pereopods 3–5 ( Fig. 25 I–K) basis length 2.1 or 2.7, 1.7 or 2.1, and 1.4 or 1.5 times distal articles combined, respectively. Pleopod 1 normal ( Fig. 25 L).

Uropod ( Fig. 25 M) peduncle 1.3–1.4 times pleonite 6, 0.87, 0.95 times exopod, and 0.87, 0.91 times 1st article of endopod, with 3 spiniform setae on inner margin. Exopod length 0.96, 1.00 times length of 1st article of endopod, with 7, 9 setae on inner margin and apical end, with 4 setae on dorsal surface, and with 2, 5 setae on ventral surface. Endopod 1st article length 3.3, 3.5 times 2nd article, with 8, 12 spiniform setae on inner margin and with 4 setae on outer margin; 2nd article with 4 spiniform setae on inner margin.

Etymology. The specific name is dedicated to Dr. Isokichi Harada in honor of his contribution to cumacean taxonomy.

Remarks. The present new species resembles E. pacifica Hart, 1930 , from the North Pacific. Based on the description by Hart (1930) and the key to species in the genus by Watling (1991), females of the E. haradai , sp. nov. can be distinguished from E. pacifica by the following characters. (1) The main flagellum of antenna 1 is longer than the 2nd article of the peduncle (subequal in E. pacifica ). (2) The basal article of this flagellum is distinctly longer than the accessory flagellum (subequal or slightly longer in E. pacifica ), (3) this basal article has 3 simple setae (no seta in E. pacifica ). (4) The uropod peduncle is shorter than the basal article of the endopod (longer in E. pacifica ). Eudorella haradai also resembles E. truncatula ( Bate, 1856) , but the females are distinguished the following. (1) The side plates of pereonites 2 and 3 are not well developed (well developed in E. truncatula ). (2) There are 2 long setae on the dorso-posterior end of pleonite 5 (no long setae in E. truncatula ). (3) The 2nd and 3rd articles of the peduncle of antenna 1 are subequal in length (2nd article longer than 3rd in E. truncatula ). (4) The branchial lobules of maxilliped 1 are small (large, well developed in E. truncatula ). (5) The propodus of pereopod 1 is subequal in length to the carpus (longer than the carpus in E. truncatula ). (6) The uropod peduncle is shorter than the exopod and endopod 1st article (longer than endopod 1st article in E. truncatula ).

Eudorella haradai , sp. nov., also resembles to E. divae Mühlenhardt-Siegel, 2005 , in the shape of the uropod, but is distinguishable from the latter by: (1) an antennal notch with two teeth on the lower end (five teeth in E. divae ); (2) The antenna 1 peduncle 2nd article is subequal in length to the 3rd (longer than 3rd in E. divae ); (3) The carpus of maxilliped 2 has 10 or more setae on the inner margin (5 setae in E. divae ); and (4) the ischium of pereopod 2 is absent, and the dactylus does not taper (the ischium is present, and the dactylus tapers in E. divae ).

Distribution. Pacific coast of northern and southern Honshu, 1982–3265 m.

Figures

FIGURE 23. Eudorella haradai sp. nov., 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, maxilliped 1; J, K, maxilliped 2; L, maxilliped 3.

FIGURE 24. Eudorella haradai sp. nov., ovigerous female. A – E, pereopods 1 – 5; F, uropod with pleonite 6.

FIGURE 25. Eudorella haradai sp. nov., subadult male. A, body, lateral view; B: anterior portion of body, from above C, anterior portion of carapace; D, antenna 1; E, antenna 2; F, maxilliped 3; G – K, pereopods 1 – 5; L, pleopod 1; M, uropod with pleonite 6.