Boreoclausia recta, Kim & Sikorski & O’Reilly & Boxshall, 2013

Kim, Il-Hoi, Sikorski, Andrey, O’Reilly, Myles & Boxshall, Geoff A., 2013, Copepods associated with polychaete worms in European seas, Zootaxa 3651 (1), pp. 1-62 : 33-35

Boreoclausia recta n. gen. et n. sp.

Type material: Holotype ♀ (dissected and mounted on a glass slide) from Galathowenia fragilis : 61.02ºN, 03.4643ºE, Troll C 2004, Stn 99r-1, depth 350 m, 04 June 2004; BMNH Reg. No. 2012.1386.

Female. Body ( Fig. 17A ) elongate, dorsoventrally depressed, with parallel lateral margins, and consisting of cephalosome, first to fifth pedigerous somites, genital complex and 1-segmented abdomen. Prosome-urosome division not marked. Cephalosome 395×275 µm, with anteriorly produced rostral area. First pedigerous somite shortest of all pedigerous somites. Second to fifth pedigerous somites with rudimentary tergite near posterodorsal border of each somite. Fourth and fifth pedigerous somites longer than anterior pedigerous somites, each incompletely subdivided into anterior and posterior halves by lateral constriction. Anterior hoop-like part of genital complex partially separated as short pseudosomite ( Fig. 17A, B ). Genital complex 197×245 µm, parallel-sided but narrowing in posterior quarter; genital apertures located dorsolaterally just posterior to midlength. Singlesegmented abdomen 140×134 µm, with deep posteromedian incision. Caudal ramus 90×40 µm (ratio 2.25:1), with 6 setae and convex medial margin; longest terminal seta 80 µm long, shorter than caudal ramus.

Rostrum as anterior prominence of cephalosome. Antennule ( Fig. 17C ) 7-segmented, with armature formula 1+spine, 8, 4+spine, 1+aesthetasc, 2, 2+aesthetasc, and 7+aesthetasc; first segment strongly expanded anterodistally; spines on first and third segments robust. Antenna ( Fig. 17D ) 4-segmented; first segment unarmed; second segment also unarmed but with row of spinules on medial margin; third segment with 1 thick, spinulose spine, 1 seta, and spinules on medial margin; terminal segment 28×17 µm, with 1 thick, spinulose spine, 3 spinuletipped setae, and 1 simple seta.

Labrum ( Fig. 17E ) with straight posterior margin ornamented with patch of spinules laterally, and several patches of minute spinules in posterior half of ventral surface. Mandible ( Fig. 17F ) tapering distally, with 1 bladelike apical element, articulated at base. Maxillule ( Fig. 17G ) lobate, with 1 inner and 2 outer setae distally. Maxilla ( Fig. 17H ) 2-segmented; proximal segment unarmed; distal segment blunt, with 1 proximal seta; distal half ornamented with spinules. Maxilliped ( Fig. 17I ) 4-segmented; first segment broad and unarmed; second segment longest, with 1 seta; short third segment unarmed; fourth segment with 1 small lateral seta and blunt apex bearing spinulose pad.

Legs 1–3 ( Figs 17J , 18A, B ) with 2-segmented exopod and small, lobate endopod, that of leg 1 spinulose, others naked. Leg 4 ( Fig. 18C ) a papilla tipped by 3 setae. Outer spines on exopod of legs 1–3 massive and spinulose. Outer margin of first exopodal segment of legs 1–3 ornamented with spinules. Armature formula of legs 1–3 as follows:

Leg 1: coxa 0-0; basis 1-0; exp. I-0; II, 1, 1; enp. (lobe)

Leg 2: coxa 0-0; basis 1-0; exp. I-0; I, I, 0; enp. (lobe)

Leg 3: coxa 0-0; basis 1-0; exp. 0-0; I, 1, 0; enp. (lobe)

Leg 5 ( Fig. 18D ) as small papilla tipped by 2 naked setae. Leg 6 represented by 1 seta and 2 spinules in genital area ( Fig. 17B ).

Male. Unknown.

Etymology. The specific name is derived from the Latin rectus meaning “straight” and alludes to the straight body, with parallel lateral margins.

Remarks. The distal blade on the mandible is articulated at its base with the segment in this species.

Figures

FIGURE 17. Boreoclausia recta n. gen. et n. sp., female. A, habitus, dorsal; B, urosome, dorsal; C, antennule; D, antenna; E, labrum; F, mandible; G, maxillule; H, maxilla; I, maxilliped; J, leg 1. Scale bars: A, 0.2 mm; B, 0.1 mm; C, 0.05 mm; D–J, 0.02 mm.

FIGURE 18. Boreoclausia recta n. gen. et n. sp., female. A, leg 2; B, leg 3; C, leg 4; D, leg 5. All scale bars: 0.02 mm.