Nodoscarus curvus, 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 : 635

Nodoscarus curvus gen. et sp. nov.

( Figs. 429 , 430 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21452 ) , paratypes (2 intact ♀♀, MNHN-IU-2014-21453), anddissectedparatype (♀, figured) from Aplidium lobatum Savigny, 1816 , Mont Dore, New Caledonia, Monniot coll., 19 March 1987.

Etymology. The specific name refers to the curved body of the new species as usual for the genus.

Description of female. Body ( Fig. 429A, B ) vermiform, cylindrical, unsegmented, curved, densely covered with numerous minute setules (setules not shown in Fig. 429 A-C). Bodylength 3.64 mm; body width 0.51 mm at widest region in middle, slightly narrowing in anterior and posterior quarters. Cephalosome poorly defined from metasome ( Fig. 429C ), with rounded anterior margin. Posterior part of body bearing horizontal sclerotization bar and weak cleft (as vestige of articulation between metasome and urosome) on dorsal surface ( Fig. 429E ), copulatory pore on ventral surface ( Fig. 429F ), and shallow posteromedian incision. Caudal rami absent (fully incorporated into posterior margin of abdomen), but 1 small caudal seta present on each side.

Rostrum ( Fig. 429D ) large, longerthanwide, weakly tapering towards rounded apex; surface covered with numerous setules. Antennule ( Fig. 429G ) as unsegmented lobe, much wider than long, densely setulose on ventral surface, armed with about 20 small setae. Antenna ( Fig. 429H ) stout, 3-segmented; coxa and basis unarmed; endopod distinctly shorter than basis, about 1.8 times longerthanwide (44×25 μm); armedwith 6 smallsetae (arranged as 2, 2, and 2) plus stout terminal claw, about half as long as endopod.

Labrum ( Fig. 429D ) broad with convex posterior margin. Mandible ( Fig. 430A ) represented only by lobate palp bearing 7 setae distally (4 on outer side and 3 on slightly projecting inner side). Maxillule ( Fig. 430B ) as lobe bearing 9 setae (3 on medial margin smaller than others). Maxilla ( Fig. 430C ) distinctly 3-segmented, with 2, 1, and 4 setae on first to third segments, respectively; setae on first segment weakly pinnate, remaining setae naked. Maxillipeds and legs absent.

Male. Unknown.

Remarks. Three characteristic features of N. curvus gen. et sp. nov. serve to differentiate itfrom its congeners: (1) the mandibular palp is armed with 7 setae; (2) the maxilla is distinctly 3-segmented and (3) is armed with 2, 1, and 4 setae on first to third segments, respectively. The presence of a single small caudal seta on the tip of the paired posteriorabdominal lobes seems to be an additional differential feature of the new species.

Figures

FIGURE 429. Nodoscarus curvus gen. et sp. nov., female. A, habitus of young adult, left; B, habitus of ovigerous adult, right; C, anterior region of body, dorsal; D, cephalosomal region, ventral; E, posterior end of body, dorsal; F, posterior end of body, ventral; G, antennule; H, antenna. Scale bars: A, B, 0.5 mm; C, E, F, 0.1 mm; D, 0.05 mm; G, H, 0.02 mm.

FIGURE 430. Nodoscarus curvus gen. et sp. nov., female. A, mandible; B, maxillule; C, maxilla. Scale bars: 0.02 mm.