Notodelphys caerulea Thorell, 1859

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 : 26

Notodelphys caerulea Thorell, 1859

( Fig. 12 )

Syn.: Notodelphys hatlassae Monniot C., 1981 new synonym.

Material examined. 2 ♀♀ (MNHN-IU-2015-3) and 1 dissected ♀ (figured) from Ascidia virginea M̹ller, 1776, Gulf of Gascogne, EVOHE, Stn 236, October–November 2009; 1 ♀ (MNHN-IU-2015-11) from A. virginea , Gulf of Gascogne, EVOHE 09, Stn 112, October–November 2009.

Supplementary description of female. Body ( Fig. 12A ) 2.97 mmlong. Freeurosome 5-segmented: anal somite ( Fig. 12B ) 168×198 μm. Caudalramus ( Fig. 12B ) 238×68 μm, about 3.5 times longer than wide and 1.4 times as long as anal somite, covered by fine setules more densely on outer and inner surfaces than on dorsal and ventral surfaces; outer seta located at 60% of ramus length.

Rostrum ( Fig. 12C ) elongated, tapering towards pointed apex. Antennule 15-segmented. Antenna ( Fig. 12D ) with 2 large subequal setae on basis representing exopod.

Mandible ( Fig. 12E ) with 4 major teeth on coxal gnathobase, second distal tooth acute; endopod with 3 setaeon first segment and 9 setaeon second. Maxillule ( Fig. 12F ) with 10 setae on precoxal arthrite, 1 seta on coxal endite, 2 unequal setae on coxal epipodite, 3 setae (including small proximal seta) on inner margin of basis, and 4 setaeon exopod; endopod 2-segmented with 1 inner seta on first segment and 4 setae on second segment. Maxilla ( Fig. 12G ) with 4, 1, 2, and 3 setae respectively on first to fourth endites of syncoxa; basis with strong claw plus 2 setae; endopod with 1, 1, and 4 setae, respectively, on first to third segments; one of setae on third endopodal segment small, setule-like. Maxilliped 3-segmented with 10, 1, and 3 setae, respectively, on first to third segments.

Legs 1–4 as in generic diagnosis. Leg 5 ( Fig. 12H ) 2-segmented. Protopod defined from somite at base, produced into elongated lateral process tipped by naked seta and ornamented with about 10 spinules along distal inner margin. Exopodal segment 31×35 μm, armed with 1 spine and 1 naked seta and ornamented with 3 or 4 spinules on inner margin near base of spine.

Remarks. When describing Notodelphys hatlassae Monniot, 1981 , Monniot (1981) apparently overlooked N. caerulea as he did not make comparisons between these two species despite their close similarity. The form of leg 5 in these two species, as illustrated by Thorell (1859), Sars (1921), Monniot (1981), and in the present account ( Fig. 12H ), does not differ significantly. In addition, the position of the lateral seta on the caudal ramus, the proportional lengths of the caudal ramus and anal somite, and the shape of the rostrum are all identical in the present material and in Monniot’s specimens. These two species also utilize the same host, Ascidia virginea . Notodelphys hatlassae Monniot, 1981 is here treated as a junior subjective synonym of N. caerulea Thorell, 1859 .

Figures

FIGURE 12. Notodelphys caenulea Thorell, 1859, female. A, habitus, right; B, anal somite and caudal ramus, dorsal; C, rostrum; D, antenna; E, mandible; F, maxillule; G, maxilla; H, right leg 5, ventral. Scale bars: A, 0.5 mm; B–H, 0.05 mm.