Ancorabolina belgicae Gheerardyn & George 2010, SP. NOV.

ANCORABOLINA BELGICAE SP. NOV.

Type locality: North-east Atlantic Ocean, Porcupine Seabight, Boxcore Bbc 01-1205 during Belgica Cruise 01/12, 51°25.9290′N, 11°46.2717′W, 880 m, collected on 7.v.2001, sample of underlying sediment [sediment covered with dead fragments of the cold-water coral Lophelia pertusa (Linnaeus, 1758)].

Material examined: From type locality: Female holotype (coll. no. COP 7695 /a–n) dissected on 14 slides. Male unknown.

Etymology: The species is named in honour of the crew of RV BELGICA.

Description: Female: Habitus (Fig. 1A) long and slender. Total body length: 342 Mm (measured from tip of rostrum to posterior end of furcal rami). Rostrum (Fig. 2B) fused to cephalothorax and elongate, tip reaching distal end of first antennular segment, with paired sensilla distally. Cephalothorax anteriorly slightly constricted, forming a ‘peak’ as described by George (2006b). Cephalothorax with sensilla and pores as figured. Posteriorly with paired lateral processes, which are strongly cuticularized and curved backwards. Posterior margin of cephalothorax with four sensillate processes. Free body somites 1–4 and anterior somite of genital double-somite with a single mediodorsal tube pore. Free body somites 1–2 with four sensillate projections at their posterior margins. Free body somites 3–4 with inner pair of small processes and outer pair of sensillate processes. Both somites of genital double-somite and following urosomite with several small projections and sensilla at their posterior margins. Posterior margin of penultimate urosomite serrate. Telson broader than long, trapezoid in lateral view (Fig. 6C), anal operculum with row of spinules.

Furcal rami (Figs 1B, 6A, C) long and slender, about 6.5 times as long as wide, with seven setae: I and II inserted closely together at posterior third of lateral margin; III inserted subapically; IV, V, and VI inserted apically; IV and V fused, V longest; VII inserted dorsally at distal margin. Outer margin with tube pore proximally. Furcal rami inserted at outer corners of telson and directed upwards (Fig. 6C).

Antennule (Fig. 2A, B) five-segmented. Armature formula: 1, 8, 5 + (1 + aes), 1, 9 + (2 + aes). First segment slightly elongate (2.5 times as long as wide), with several long spinules along inner surface. Second segment with a small, round bump near middle of outer margin. Second and third segments with several long spinules along outer margin, both nearly equal in length to first segment. Fourth segment shortest, nearly square in shape. Fifth segment slightly shorter than third one.

Antenna (Fig. 2C) with allobasis; exopod absent; abexopodal margin of allobasis with longitudinal row of spinules and one slender seta. Endopod with several spinules, laterally with two bipinnate spines. Apical armature consisting of two unipinnate spines, three long geniculate setae, and one small bare seta (fused basally to seta next to it). Subapically with two cuticular spinular frills.

Labrum well developed (Fig. 3A).

Mandible (Fig. 3B) with strong gnathobase bearing several incised blades and one additional seta. Mandibular palp one-segmented, with two inner, one outer, one subapical, and two apical setae.

Maxillule (Fig. 3C, D). Praecoxal arthrite with two setae on anterior surface; apical armature consisting of six bare and two pinnate spines, and one slender seta. Coxal endite with one well-developed, pinnate spine. Basis, endopod, and exopod fused, bearing eight setae.

Maxilla (Fig. 3E). Syncoxa bearing two endites, with long spinules along outer margin. Proximal endite with two setae and one unipinnate spine fused to endite. Distal endite with three setae, one of which is plumose. Basis drawn out into a claw, accessory armature consisting of three bare setae. Endopod reduced and represented by two bare setae.

Maxilliped (Fig. 3F) long and slender, prehensile. Syncoxa apically with a bipinnate seta and several spinules. Basis with a row of small spinules along inner margin and several spinules along outer margin. Endopod drawn out into a long, narrow, curved, finely pinnate claw with one accessory seta at base.

P1 (Fig. 4A) with two-segmented endopod and exopod. Coxa about 1.5 times as long as wide. Basis longer than coxa, slightly prolonged transversely, with inner and outer bipinnate seta. Exp-1 with outer spine, exp-2 with five geniculate setae. Enp-1 twice as long as exopod, with a row of long spinules along inner margin. Enp-2 much smaller, apically with two bare setae (one claw-like and one geniculate).

P2–P4 (Figs 4B, C, 5A, B). Basis transversely elongate, with one tube pore in distal half of anterior surface, outer distal seta bipinnate. Exopods three-segmented, outer spines elongate. Endopods two-segmented; first segment very small, without ornamentation. Enp-2 of P2–P4 very long, with two apical setae; enp-2 of P3–P4 additionally with one inner seta. Enp-2 of P2 with inner spinules, of P3–P4 with inner and outer spinules. Armature formula as in Table 1.

P5 (Fig. 6B). Baseoendopod with long outer spinules. Endopodal lobe vestigial, with two small setae and two tube pores. One additional tube pore inserts at the base of the setophore. Exopod distinct and elongate, with one inner, two distal, and two outer bipinnate setae, one tube pore and with long spinules near outer margin.

Genital field (Fig. 6A). P6 represented by two small cuticular plates.