Archinotodelphys monnioti, Kim & Boxshall, 2020

Kim, Il-Hoi & Boxshall, Geoff A., 2020, A revision of the family Archinotodelphyidae Lang, 1949 (Copepoda: Cyclopoida Oithonida), with the recognition of 15 new species, Zootaxa 4801 (1), pp. 1-56 : 24-28

Archinotodelphys monnioti sp. nov.

(Figs. 12–14)

Type Material. Holotype ♀ (MNHN-IU-2014-21198; intact), 2 paratypes (1 ♀, MNHN-IU-2014-21199, and 1 ♂, MNHN-IU-2014-21200; both dissected)

Type host. Pareugyrioides galatheae (Millar, 1959) (MNHN-IT-2008-6004 = MNHN S3 /PAR.A/11) .

Type locality. SW Heard I., Kerguelen Plateau , MD03 /ICTHYO cruise, RV Marion Dufresne, Stn 12-36-CP08 (55°50’S, 69°36’E), depth 4200-4225 m, 11 April 1974 .

Additional material. 1 ♀ (dissected) in Pareugyrioides digitus Monniot C., 1997 , (MNHN-IT-2008-6002 = MNHN S3 /PAR.A/3), Cape Verde basin, Mauritanie Eumeli 2 cruise, RV Atalante, Stn CP 01 (18°24.5´N, 21°09.8´W), depth 3086 m, IFREMER coll., 24 January 1991 .

Etymology. The new species is named in honour of Claude Monniot, in recognition of his contribution to knowledge of copepods living in association with tunicates.

Female. Body (Fig. 12A) relatively large, 2.46 mm long; prosome 1.40 mm long; all prosomites with rounded posterolateral corners; cephalosome 618×887 μm; first pedigerous somite narrower than dorsal cephalosomic shield and second pedigerous somite. Urosome 5-segmented: fifth pedigerous somite 287 μm wide. Genital double-so- mite 298×225 μm; bearing paired genital apertures dorsolaterally at about 41% of double-somite length. Three free FIG. 12. Archinotodelphys monnioti sp. nov. paratype female. A, habitus, dorsal; B, left caudal ramus, dorsal; C, rostrum; D, antennule; E, antenna; F, labrum; G, mandible; H, paragnath; I, maxillule. Scale bars: A, 0.5 mm; B–E, 0.1 mm; F–I, 0.05 mm.

FIG. 13. Archinotodelphys monnioti sp. nov. paratype female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5; G, right genital aperture, dorsal; H, right genital aperture, lateral. Scale bars: A–F, 0.1 mm; G, H, 0.05 mm.

FIG. 14. Archinotodelphys monnioti sp. nov. male. A, habitus, dorsal; B, urosome, ventral; C, antennule; D, leg 5. Scale bars: A, 0.2 mm; B, C, 0.1 mm; D, 0.05 mm.

abdominal somites 145×181, 116×167, and 145×167 μm, respectively. Caudal ramus (Fig. 12B) about 4.1 times longer than wide (275×67 μm); armed with 6 setae; lateral seta located about at 42% of ramus length; outer distal and 2 mid-terminal setae (setae III–V) naked; 2 mid-terminal setae without annulation at base; other 3 setae weakly pinnate; dorsal seta (seta VII) located at 70% of ramus length.

Rostrum (Fig. 12C) narrow, 229×156 μm, with rounded apex. Antennule (Fig. 12D) 17-segmented; armature formula 3, 5, 8, 2, 2, 6, 4+aesthetasc, 1, 2, 1, 2, 1+aesthetasc, 1, 1, 2, 2+aesthetasc, and 7+aesthetasc; aesthetascs small, setiform; all setae naked. Antenna (Fig. 12E) with short unarmed coxa; basis with inner distal seta plus 2 exopodal setae, and ornamented with several setules on inner margin; endopodal segments 118, 80, 76 μm long, respectively; armed with 1, 4, and 6 plus claw; terminal claw curved and slender; 1 seta on second segment and 3 setae on third with rounded tips.

Labrum (Fig. 12F) with large posteromedian lobe ornamented with spinules and setules along free margins; posterolateral corners also with spinules. Mandible (Fig. 12G) with complex cutting edge of coxal gnathobase bearing 7 teeth, 2 setae and many spinules; basis with 1 seta on inner margin; exopod distinctly 4-segmented with 5 setae (1, 1, 1, and 2 on first to fourth segments); endopod 2-segmented with 4 setae on first segment and 10 setae on second. Paragnath (Fig. 12H) forming tapering lobe ornamented with setules on medial surface. Maxillule (Fig. 12I) with 10 setae on precoxal arthrite, 1 of which located on ventral papilla; coxal endite and epipodite with 1 and 2 setae, respectively; basis with 1 spine and 6 setae on medial margin; exopod with 4 setae; endopod 2-segmented with 6 setae on first and 4 setae on second segment. Maxilla (Fig. 13A) 6-segmented; precoxa and coxa clearly defined; precoxa with 3 setae and 1 small spine on proximal endite and 1 seta on distal endite; coxa with 2 setae on proximal endite and 3 setae on distal endite; basis with 1 claw and 2 setae; endopod 3-segmented, third segment small; armed with 2, 1, and 4 setae on first to third segments. Maxilliped (Fig. 13B) 4-segmented with 9, 1, 3, and 3 setae on first to fourth segments; setae on first segment grouped as 1, 4, and 4 from proximal to distal.

Legs 1–4 with 3-segmented rami (Fig. 13C–E) and same armature formula as preceding species. All setae on legs pinnate. Inner distal spine on basis of leg 1 spinulose.

Leg 5 (Fig. 13F) consisting of protopodal segment with outer seta and exopodal segment about 2.4 times longer than wide (189×80 μm), armed with 4 setae; setal lengths 375, 410, 161, and 250 μm, from outer to innermost. Leg 6 (Fig. 13G, H) consisting of 1 seta, 1 spine and 1 spiniform process on genital operculum.

Male. Body (Fig. 14A) length 1.53 mm; prosome length 855 μm; cephalosome 406×545 μm. Urosome (Fig. 14B) 6-segmented; fifth pedigerous somite 159 μm wide; genital somite sub-square, 125×150 μm; 4 free abdomi- nal somites 106×112, 91×102, 68×91, and 91×95 μm, respectively. Caudal ramus about 5 times longer than wide (184×36 μm); all 6 caudal setae naked.

Rostrum as in female. Antennule (Fig. 14C) 15-segmented and geniculate between thirteenth and fourteenth segments; armature formula 3, 5, 6, 2, 2, 2, 2, 2, 2, 4+aesthetasc, 1, 2, 2, 4, and 11+aesthetasc; third and tenth segments each with rudiment of articulation in mid segment. Antenna, labrum, mandible, paragnath, maxillule, maxilla, maxilliped, and legs 1–4 as in female.

Leg 5 (Fig. 14D) protopodal segment wider than long; exopodal segment about 2.1 times longer than wide (74×36 μm), armed with 4 setae; lengths of setae 48, 71, 117, and 93 μm, from outermost to inner; inner seta stiff. Leg 6 represented by 2 pinnate and 1 small, spiniform setae on genital operculum.

Remarks. The new species possesses a 4-segmented maxilliped armed with a total of 16 setae. This is a unique character state, distinguishing A. monnioti sp. nov. from A. antarcticus sp. nov. (with 17 setae) and A. curtus sp. nov. (with 14 or 15 setae), and A. illgi sp. nov., A. hexasetosus sp. nov., A. cincutus sp. nov., and A. bimerus sp. nov. (with 14 setae). The setal formula of the 3-segmented endopod of the maxilla (2, 1, 4) is shared only with A. momus sp. nov. but this species has 6 setae on the exopodal segment of leg 5 rather than 4 setae as in A. monnioti sp. nov.

The new species occurs on two different host species, both belonging to the same genus Pareugyrioides Hartmeyer, 1914 .