Haploniscus bihastatus, 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 : 5

Haploniscus bihastatus n. sp.

( Figs 2–5 )

Holotype: DIVA 2-HA233, adult male (stage VI), length 1.7 mm, coll.: RV Meteor, M63/2, DIVA 2 expedition, EBS station 89-6, 0°42.95’ N 5°31.29’ W, Guinea Basin, southeast Atlantic, ZMH K- 42426.

Paratypes: DIVA 2-HA330, adult male, length 1.8 mm, same locality as holotype, ZMH K- 42427. DIVA 1-HA235, adult male, length 1.75 mm, DIVA 1-HA276, adult male, length 1.87 mm, coll.: RV Meteor, M48/1, DIVA 1 expedition, EBS station 340-9, 18°18.3’ S 4°41.3’ E, 5395 m, Angola Basin, southeast Atlantic, ZMH K- 42428.

Etymology. From the Latin bi, meaning “two” and hastatus, “armed with a hasta”, a spear used by early Roman legionnaires. The name refers to the shape of the two large pleotelson processes, which resemble that of a hasta spearhead.

Diagnosis. Rostrum 0.5 head length. Pereonites 3–5 broadest. Posterior angles of pereonite 4 and anterior angles of pereonite 5 slightly produced; posterior body outline constricted in dorsal view, due to strong narrowing of posterior pereonites. Lateral margins of pleotelson slightly convex; pleotelson process length 0.9 pleotelson length, 2.7 width. Pleopod 1 lateral margins tapering only slightly, abruptly narrowing into neck (narrowest part); distance basal margin–neck 0.8 total length, neck width 0.4 maximum width; distolateral margins with small process each. Pleopod 2 protopod inner margin strongly concave; endopod length nearly 3.0 protopod length, 11.0 width; article 2 length 8.1 article 1 length.

Description (stage VI male). Body ( Fig. 2 A–C) length 2.6 width. Head length 0.6 width. Pereonites 1 and 7 narrowest. Posterior angles of pereonites 2–7 and anterior angles of pereonites 3–5 acute;. Pleotelson length 0.3 body length, 0.8 width.

Antenna 1 ( Fig. 3 F) peduncular article 1 length 1.6 width, with 2 penicillate setae distally; article 2 length 1.1 article 1 length, 2.0 width, with 2 simple and 4 penicillate setae distally; article 3 length 0.4 article 1 length, width 0.4 article 1 width, with 1 simple seta distally. Flagellum with 4 articles; article 1 shortest, article 2 longest, about 2.0 article 1 length, with 1 aesthetasc; article 3 with 2 aesthetascs and 1 simple seta, article 4 with 3 aesthetascs and 3 simple setae.

Antenna 2 ( Fig. 3 E) peduncular articles 1 and 2 of subequal length and subequal width, article 2 with 2 simple setae; article 3 length 1.8 article 2 length, 1.3 width, with 1 simple seta distally, dorsal tooth with 2 simple setae; article 4 length 0.7 article 3 length, 0.9 width; article 5 length 2.2 article 3 length, 2.6 width, with at least 1 small penicillate seta and 1 simple seta; distal articles missing.

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

Pleopod 1 ( Fig. 5 A) length 0.8 pleotelson length, 2.0 width; widest part after 0.25 of its length.

Pleopod 2 ( Fig. 5 B) protopod length 2.3 width, with about 10 long setae along outer margin.

Pleopod 3 ( Fig. 5 C) endopod length 1.9 width. Exopod length 0.6 endopod length, 2.7 width.

Pleopod 4 ( Fig. 5 D) endopod length 2.1 width. Exopod length 0.5 endopod length, 3.4 width, plumose seta length about 2.3 exopod length.

Pleopod 5 ( Fig. 5 E) length 2.3 width.

Uropod ( Fig. 2 C) distal article extending beyond posterior margin, not reaching tips of pleotelson processes.

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

Figures

FIGURE 2. Haploniscus bihastatus n. sp., male holotype, ZMH K- 42426; A, habitus, dorsal view; B, habitus, lateral view; C, posterior body, ventral view. Scale bar 1 mm.

FIGURE 3. Haploniscus bihastatus n. sp., male paratype, ZMH K- 42427; A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, antenna 2, with lateral view of article 3; F, antenna 1. Scale bars 0.1 mm.

FIGURE 4. Haploniscus bihastatus n. sp., male paratype, ZMH K- 42427; A, pereopod 5; B, pereopod 6; C, pereopod 7. Scale bar 0.1 mm.

FIGURE 5. Haploniscus bihastatus n. sp., male paratype, ZMH K- 42427; A, pleopod 1; B, pleopod 2; C, pleopod 3; D, pleopod 4; E, pleopod 5. Scale bar 0.1 mm.