Scolecodes helicinus, Kim & Boxshall, 2020

Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), Megataxa 4 (1), pp. 1-6 : 608-610

publication ID	https://doi.org/ 10.11646/megataxa.4.1.1
DOI	https://doi.org/10.5281/zenodo.5700574
persistent identifier	https://treatment.plazi.org/id/03C487CB-ED0E-3854-FF4D-FC57FEA7FA4E
treatment provided by	Plazi
scientific name	Scolecodes helicinus
status	sp. nov.

Treatment

Scolecodes helicinus sp. nov.

( Figs. 410–414 View FIGURE 410 View FIGURE 411 View FIGURE 412 View FIGURE 413 View FIGURE 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.

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-0	8	6
Leg 2	0-0	1-0	11	8 or 9
Leg 3	0-0	1-0	12 or 13	9
Leg 4	0-1	1-0	11 to 13	8
Leg 5	absent.

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 View FIGURE 410 ) 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 View FIGURE 410 ) present on ventral surface lateral to oral region. Genital area positioned dorsally near posterior end of prosome ( Fig. 410C View FIGURE 410 ). Abdomen ( Fig. 410C View FIGURE 410 ) unsegmented, widerthan long (64×90 μm), divided from prosome by faint suture line, not fused with prosome on ventral surface. Caudal rami ( Fig. 410C View FIGURE 410 ) 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 View FIGURE 410 ) tapering, directed anteriorly, usually with pair of small papillae apically ( Fig. 410D View FIGURE 410 ). Antennule ( Fig. 410E View FIGURE 410 ) 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 View FIGURE 410 ) 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 View FIGURE 410 ) 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 View FIGURE 410 ) as densely setulose lobe. Maxillule ( Fig. 410I View FIGURE 410 ) lobate, bearing 7 plumose setae and with setulose medial margin. Maxilla ( Fig. 410J View FIGURE 410 ) 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 View FIGURE 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 View FIGURE 412 ) 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 View FIGURE 412 ) about 2.6 times longer than wide (55×21 μm).

Rostrum, antennule, and antenna ( Fig. 412E View FIGURE 412 ) 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 View FIGURE 412 ) as in type material.

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