Scolecodes rectus Kim & Boxshall 2020, sp. nov.

Scolecodesrectus sp. nov.

(Figs. 408, 409)

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21438) from Boltenia hirta Monniot C. & Monniot F., 1977 (Type MNHN-IT-2008-1485 = MNHN S2/BOL.A/7), SW of Heard Island (55°49.5’S, 69°35.7’E), depth 4200-4225 m, MNHN coll., 11 April 1974.

Etymology. The name is derived from the Latin rect (=straight), alluding to the linear body of the female of the new species.

Descriptionoffemale. Body (Fig. 408A) elongate, cylindrical, straight, consisting of prosome and small unsegmented abdomen: bodylength 6.21 mm; maximum body width 0.86 mm in middle of prosome. Cephalosome (Fig. 408B) small, articulated from metasome, narrowing anteriorly. Metasome with 4 original pedigerous somites defined by incomplete dorsal sutures.Anteriorpart of body from rostrum tolevel of leg 4 occupying about 30% of total body length; legs 1–4 separated by equal intervals. Fourth pedigeroussomiteexpandedposteriorly, incorporatingfifth pedigerous somite and forming brood pouch. Copulatory pore positioned on posteroventral surface of incorporated genitalsomite. Abdomen (Fig. 408C) small, unsegmented, longerthan wide (216×180 μm), not articulated from prosome, inserted into posteroventral surface of prosome. Caudal rami (Fig. 408D) about 2.8 times longerthan wide (125×45 μm), tapering in distal half, ornamented with scattered papillae: armed with 6 smallsetae (2 outer lateral plus 4 distal and subdistal).

Rostrum (Fig. 408B) directed anteriorly, tapering. Antennule (Fig. 408C) unsegmented, consistingof greatly expanded, globular proximal part and narrow, digitiform distal part; armed with 4 setae on proximal part and about 8 setaeon distal part. Antenna (Fig. 408F) 3-segmented, consistingof short coxa, broad basis, and unsegmented endopod; basis slightly longerthan wide; endopod tapering, terminating in claw and bearing 1 outer and 4 inner smallsetae at base of claw.

Labrum (Fig. 408G) simple, with slightly produced mid-region of free posterior margin. Mandible with coxa represented by setulose lobe (Fig. 408G); palp forming rectangular lobe (Fig. 408H) bearing 3 large naked setae distally on medial margin and 3 small pinnate setae plus 1 pointed, setiform process on distal margin. Maxillule (Fig. 408I) lobate, bearing 7 pinnate setae (3 large setae on medial margin and 4 smaller, apical or subapical setae). Maxilla (Fig. 408A) lobate, unsegmented, armed distally with 3 naked setae. Maxilliped absent.

Legs 1–4 (Fig. 409 B-E) biramous, each consisting of unsegmented protopod, 2-segmented exopod and 1- segmented endopod. Protopods armed with outer seta (derived from basis) only. Both rami obscurely defined from protopod; all setae naked, most spiniform, short but thick, with nipple-like tip. Armature formula for legs 1–4 as follows:

Male. Unknown.

Remarks. Scolecodes rectus sp. nov. shares the possession of 2-segmented exopods on legs 1–4 only with S. pugetensis sp. nov. Thischaracterstate distinguishesthe new species from the type species, S. huntsmani. It differs from S. pugetensis sp. nov. as follows: the abdomen is longer than wide (vs. as long as wide in S. pugetensis sp. nov.), the mandible carries a setiform apical process in addition to 6 setae (vs. no setiform process in S. pugetensis sp. nov.), the maxillule is armed with 7 setae (vs. 6 setae in S. pugetensis sp. nov.), the maxilla is armed with 3 setae (vs. 4 setae in S. pugetensis sp. nov.), and the rami of legs 1–4 are armed with fewer setae.