Haploniscus machairis, Brökeland, Wiebke, 2010

Brökeland, Wiebke, 2010, Description of four new species from the Haploniscus unicornis Menzies, 1956 complex (Isopoda: Asellota: Haploniscidae), Zootaxa 2536, pp. 1-35 : 17

Haploniscus machairis n. sp.

( Figs 9–11 )

Holotype: DIVA 2-HA510, adult male (stage VI), length 1.51 mm, coll.: RV Meteor, M63/2, DIVA 2 expedition, EBS station 90-7, 0°40.49’ N 5°29.71’ W, 5142 m, Guinea Basin, southeast Atlantic, ZMH K- 42431.

Paratypes: DIVA 2-HA416, adult male, length 1.55 mm, same locality as holotype, ZMH K- 42432. DIVA 2-HA235–237, -HA331, adult males, length 1.45–1.54 mm, coll.: RV Meteor, M63/2, DIVA 2 expedition, EBS station 89-6, 0°42.95’ N 5°31.29’ W, 5142 m, Guinea Basin, ZMH K- 42433. DIVA 1-HA56, adult male, length 1.49 mm, coll.: RV Meteor, M63/2, DIVA 1 expedition, EBS station 318-1, 22°20.0’ S 3°18.3’ E, 5125 m, Angola Basin, ZMH K- 42434. DIVA 1-HA264, adult male, length 1.63 mm, coll.: RV Meteor, M63/2, DIVA 1 expedition, EBS station 340-1, 18°18.3’ S 4°41.3’ E, 5395 m, Angola Basin, ZMH K- 42435.

Etymology. The Greek machairis is the diminutive for machaira, the name for a bent sword. The name refers to the rostrum, which has a similar shape.

Diagnosis. Rostrum 0.5 head length. Pereonites 4 and 5 broadest, body tapering anteriorly and posteriorly; posterior angles of pereonite 4 and anterior angles of pereonite 5 slightly produced. Lateral margins of pleotelson tapering posteriorly. Pleotelson process length 0.5 pleotelson length, 2.0 width. Pleopod 1 lateral margins tapering continuously towards neck, slightly convex; distance basal margin–neck 0.8 total length, neck width 0.5 maximum width. Distolateral margins with minute process each. Pleopod 2 inner margin concave; endopod length 2.8 protopod length, 10.0 width; article 2 length 4.3 article 1 length.

Description (stage VI male). Body ( Fig. 9 A–C) length 2.6 width. Head length 0.6 width. Posterior angles of pereonites 2–7 and anterior angles of pereonites 3–5 acute. Pleotelson length 0.3 body length, 0.9 width.

Antenna 1 ( Fig. 10 G) peduncular article 1 length 1.8 width, with 3 penicillate setae distally; article 2 length 1.05 article 1 length, 2.2 width, with 2 simple and 4 penicillate setae distally; article 3 length 0.3 article 1 length, width 0.5 article 1 width, with 2 simple setae distally. Flagellum with 4 articles; article 1 shortest, articles 2–4 of subequal length about 1.5 article 1 length; article 2 with 1 aesthetasc and 1 simple seta; article 3 with 2 aesthetascs, article 4 with 2 aesthetascs and 2 simple setae.

Antenna 2 ( Fig. 10 F) peduncular article 2 with 1 simple seta; article 3 length 1.75 width, with 1 simple seta distally and 2 simple setae dorsally, dorsal tooth with 2 simple setae; article 4 0.8 article 3 length, 1.4 width, with 2 simple setae; article 5 length 1.6 article 3 length, 2.5 width, with at least 7 simple setae; article 6 length 2.2 article 3 length, 5.0 width, with at least 3 penicillate and 4 simple setae. Flagellum with 11 articles, each article with up to 4 simple setae.

Pereopods ( Figs 10 A–E; 11A, B): Basis of all pereopods with 2 long simple setae ventrally; basis of pereopods 2–4 with 2 penicillate setae, of pereopods 5–6 with 3 penicillate setae, of pereopod 7 with 1 penicillate seta dorsally. Ischium with 1 seta dorsally and 1 or 2 setae ventrally. Merus with 2 simple setae of different length distodorsally, and 2 or 3 setae distoventrally. Carpus with 2 or 3 simple setae ventrally; with 1 short simple seta, pereopods 2–7 with 1 penicillate seta distodorsally. Propodus with 2–5 setae ventrally, peropods 1–3 with 1 simple seta distodorsally (broken off on pereopods 4–7), pereopods 2–7 with 1 penicillate seta distodorsally (broken off on pereopod 6). Dactylus of pereopods 1–4 with 4 and of pereopods 5–7 with 2 setae near insertion of unguis.

Pleopod 1 ( Fig. 11 C) length 0.6 pleotelson length, 1.9 width; widest part after 0.2 of its length.

Pleopod 2 ( Fig. 11 D) protopod length 2.1 width, with about 9 long setae along outer margin.

Pleopod 3 ( Fig. 11 E) endopod length 1.9 width. Exopod length 0.7 endopod length, 1.7 width.

Pleopod 4 ( Fig. 11 F) endopod length 2.3 width. Exopod length 0.6 endopod length, 2.7 width, plumose seta broken off.

Pleopod 5 ( Fig. 11 G) length 2.2 width.

Uropod ( Fig. 9 C) extending beyond posterior margin, not reaching tips of pleotelson processes.

Distribution. Found in the Guinea Basin and Angola Basin, Southeast Atlantic.

Figures

FIGURE 9. Haploniscus machairis n. sp., male holotype, ZMH K- 42431; A, habitus, lateral view; B, habitus, dorsal view; C, posterior body, ventral view. Scale bar 1 mm.

FIGURE 10. Haploniscus machairis n. sp., male paratype, ZMH K- 42432 (A – E) and K- 42433 (F, G); A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, antenna 1; G, antenna 2, with lateral view of article 3. Scale bars 0.1 mm.

FIGURE 11. Haploniscus machairis n. sp., male paratype, ZMH K- 42432; A, pereopod 6; B, pereopod 7; C, pleopod 1; D, pleopod 2; E, pleopod 3; F, pleopod 4; G, pleopod 5. Scale bars 0.1 mm.