Contouraelliptica, 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 : 568-570

Contouraelliptica gen. etsp. nov.

( Fig. 381 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21417 ) from a colonial ascidian of Aplidium sp., Porto Belo, Santa Catarina, Brazil, da Rocha coll., 02 March 1987.

Etymology. The specific name refers to the elliptical shaped body of the adult female of the new species.

Descriptionoffemale. Body ( Fig. 381A ) fusiform, with rudimentary free urosome; body length 2.98 mm. Cephalosome weakly defined from anterior part of prosome by indistinct dorsal suture line; greatest dorsoventral depth of prosome 1.38 mm near posterior third. Prosome-urosome boundary not defined, with fifth pedigerous and genital somites incorporated into swollen prosome. Freeurosome ( Fig. 381B ) extremely reduced, wider than long, unsegmented, and distally incised. Leg 5 and gonopore positioned ventrodistally on prosomeurosome complex ( Fig. 381B ). Caudal rami and caudal setae absent.

Rostrum ( Fig. 381C ) longerthanwide (147×83 μm), widest at 40% of length, tapering distally towards blunt apex. Antennule ( Fig. 381D ) lobate, wider than long (78×95), subcircular, bearing 3 or 4 wrinkles on posterior surface; armed with 2 small setae proximally on anterior margin and 2 setae at apex; ornamented with minute setules (or spinules) along anterior surface. Antenna ( Fig. 381E ) narrow, probably 3-segmented; coxa and basis unarmed; endopod missing in holotype.

Labrum ( Fig. 381F ) broad with large paired ventrolateral tubercles; tubercles digitiform distally and curved medially; ornamented with spinules; posterior margin straight and smooth. Mandible ( Fig. 381G ) consisting of coxa and reduced palp: coxal gnathobase similar to that of C. globosa gen. et sp. nov., with serrate medial margin: palp tapering, unsegmented, bearing 3 smallsetae (or tubercles) mediodistally. Maxillule ( Fig. 381H ) similartothatof C. globosa gen. etsp. nov., with 3 large spiniform teeth on precoxal arthrite; outer lobe of palp tipped with 1 minute setule; inner lobe with 1 large seta mediodistally and 5 apically pointed tubercles. Maxilla ( Fig. 381I ) 4-segmented; syncoxawith 2 small setae medially; basis with 1 seta and drawn out to large claw bearing 4 teeth distally on convex proximal margin; endopod with 1 small seta on first segment and 2 very unequal setae on second. Maxilliped ( Fig. 381J ) as small lobe tipped with 2 equal, plumose setae.

Leg 1 ( Fig. 381K ) plate-like, unarmed and unornamented, distally bilobed, with weak inner lobe (endopod).Legs 2–4 absent.Leg 5 ( Fig. 381B ) represented by 2 pairs of conical, sclerotized processes.

Male. Unknown.

Remarks. Contouraelliptica gen. etsp. nov. iseasily distinguished from its only congener, the type species C. globosa gen. et sp. nov., by the markedly different body form of the female. Other differences include, the unsegmented urosome (vs. 2-segmented urosome in C. globosa gen. et sp. nov.), the labrum is specialized and bears paired ventrolateral tubercles (vs. these tubercles lacking in C. globosa gen. et sp. nov.), the syncoxa of the maxilla bears a single seta (vs. 2 setae), and the maxilliped is armed with 2 setae (vs. 1 seta).

Figures

FIGURE 381. Contoura elliptica gen. et sp. nov., female. A, habitus, right; B, posterior part of body, ventral; C, rostrum; D, antennule; E, proximal part of antenna; F, labrum; G, mandible; H, maxillule; I, maxilla; J, maxilliped; K, leg 1. Scale bars: A, 0.5 mm; B, 0.1 mm; C–F, K, 0.05 mm; G–J, 0.02 mm.