Nodoscarus quadrisetatus, 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 : 645

Nodoscarus quadrisetatus gen. et sp. nov.

( Fig. 438 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21461 ) from Leptoclinides robiginis Monniot, F., 1989 , south lagoon , New Caledonia.

Etymology. The specific name refers to the presence of four setae on the mandible.

Descriptionoffemale. Body ( Fig. 438A ) vermiform, elongate, cylindrical, unsegmented, almost straight, surface densely covered with fine setules (setules not shown in Fig. 438A, B ). Bodylength 6.25 mm; body width 0.93 mm in middle. Paired convoluted ovaries, occupying 70% of body length, visible through body wall. Body tapering slightly anteriorly. Posterior end of body ( Fig. 438B ) bilobed, with shallow median (anal) incision.

Rostrum absent ( Fig. 438C ). Antennule ( Fig. 438C ) as broad, semicircular lobe, surface covered with fine setules plus 1 or 2 small setae apically. Antenna ( Fig. 438D ) stout, 3-segmented: coxa short; basis only slightly longerthan wide, unarmed; endopod about 1.4 times longer than wide (24×17 μm): armed with 1 subdistal and 3 small distal setae, plus short, stout terminal claw, half as long as endopod.

Labrum not discernible. Only 2 pairs of mouthparts present. Mandible (first pair, Fig. 438E ) lobate, tipped with 4 naked setae. Maxillule (second pair, Fig. 438F ) lobate, tipped with 2 setae. Large, anteriorly-directed, post-oral protuberance present posterior to oral region ( Fig. 438C ). Maxillae, maxillipeds, and legs absent.

Male. Unknown.

Remarks. Nodoscarus quadrisetatus gen. et sp. nov. is best compared with N. senisetatus gen. et sp. nov., because both of these two species retain only two pairs of mouthparts and share the presence of 2 setae on the second pair (the maxillules). The new species can be distinguished from N. senisetatus gen. et sp. nov. by the lack of a rostrum and by the possession of 4 setae on the mandible (vs. 6 setaein N. senisetatus gen. etsp. nov.).

Figures

FIGURE 438. Nodoscarus quadrisetatus gen. et sp. nov., female. A, habitus, ventral; B, posterior end of body, ventral; C, cephalic region, ventral; D, antenna; E, mandible; F, maxillule. Scale bars: A, 1 mm; B, 0.1 mm; C, 0.05 mm; D–F, 0.02 mm.