Scolecodes helicinus sp. nov.

(Figs. 410–414)

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21439), paratypes (7 intact ♀♀, MNHN-IU-2014- 21440), and dissected paratypes (4 ♀♀, figured) in thin membranous cysts in the colonial ascidian Polyclinum isipingense Sluiter, 1898 (MNHN-IT-2008-XXX = MNHN A1/ POL.B/108), ATIMOVATAE TR07, Madagascar (25°01’S, 47°00’E), depth 12-16 m, MNHN coll., 01 May 2010.

Additional material. 18 ♀♀ (MNHN-IU-2018- 1912) and 2 dissected ♀♀ from Eudistoma sp., New Caledonia (18°28’15″S, 163°04’40″E), depth 12-15 m; 4 ♀♀ (MNHN-IU-2018-1913) from Eudistoma sp., Mabul, Malaysia (04°14.51’N, 118°37.32’E), 16 January 2004; 1 ♀ (MNHN-IU-2018-1914) and 1 dissected ♀ from Eudistoma sp., Tulear, southwestern coast of Madagascar.

Etymology. The name is derived from the Greek helic (=a coil) and refers to the coiled body of the female of the new species.

Descriptionoffemale. Body (Fig. 410A) extremely elongate, cylindrical, coiled in various ways after fixation, consisting of unsegmented prosome and small unsegmented abdomen. Body length variable, 7.23 mm in figured largest specimen; body width 0.31 mm. Anterior part of body from rostrum to level of leg 4 occupying 14% of total body length. Cephalosome about 200×280 μm, expanded laterally, with narrow antennal region (144 μm wide) and tapering rostral region (62 μm wide); pair of blunt digitiform processes (indicated by arrowhead in Fig. 410D) present on ventral surface lateral to oral region. Genital area positioned dorsally near posterior end of prosome (Fig. 410C). Abdomen (Fig. 410C) unsegmented, widerthan long (64×90 μm), divided from prosome by faint suture line, not fused with prosome on ventral surface. Caudal rami (Fig. 410C) about 2.2 times longerthan wide (58×27 μm), slightly broadened in middle: armed with 6 small setae (1 outer lateral, 1 dorsal, and 4 distal).

Rostrum (Fig. 410B) tapering, directed anteriorly, usually with pair of small papillae apically (Fig. 410D). Antennule (Fig. 410E) unsegmented, divisible into globular proximal part and narrow, digitiform distal part; armed with about 4 setae on proximal part and 9 setae on distal part (setation hardly observable and apparently variable).Antenna (Fig. 410F) incompletely 3-segmented; coxa and basis obscurely demarcated, both unarmed; unsegmented endopod bearing 2 setae and drawn out into elongate, weakly curved claw.

Labrum small, hardly dissectable. Mandible (Fig. 410G) unsegmented, consistingof narrow stalk and expanded distal part, armed with 3 pinnate setae on medial marginand 1 or 2 smallsetae apically; ornamented with several minute setules. Paragnath (Fig. 410H) as densely setulose lobe. Maxillule (Fig. 410I) lobate, bearing 7 plumose setae and with setulose medial margin. Maxilla (Fig. 410J) incompletely 2-segmented, tapering, armed with 1 and 3 small, naked setae on first and second segments, respectively. Maxilliped absent.

Legs 1–4 (Fig. 411 A-D) shortand broad, each consistingof 2-segmented protopod and unsegmented rami; rami of all legs broader than long. Inner coxal seta absent in legs 1–3, but present in leg 4. Small outer seta present on basis of legs 1–4. All setae on rami broad, with narrow, rounded tip. Armature formula for legs 1–4 as follows:

Brief description of female associated with Eudistoma sp. in New Caledonia

Body(Fig. 412A, B) similarinformtothatof typematerial, but smaller. Body lengths of 2 dissected specimens 4.26 and 4.68 mm; widths 0.18 and 0.17 mm, respectively. Cephalosome 205 μm wide, and antennal region 146 μm wide. Caudal ramus (Fig. 412C) about 2.6 times longer than wide (55×21 μm).

Rostrum, antennule, and antenna (Fig. 412E) as in type material. Mandible similar to that of type material, but with 7 more distinct, pinnate setae, without setules. Maxillule and maxilla (Fig. 412G) as in type material.

Legs 1–4 as in type material in form, with armature formula as follows: