Ooneidescalifornica, 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 : 619

Ooneidescalifornica sp. nov.

( Fig. 419 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21443 ) from an ascidian of the family Didemnidae , La Jolla, California, USA, R A. Lewin coll., 12 December 1985.

Etymology. The species name refers to the type locality, California.

Descriptionoffemale. Body ( Fig. 419A ) ovoid, laterally compressed, unsegmented, with minute abdomen. Bodylength (prosome length) 2.29 mm; dorsoventral depth 1.66 mm. Cephalosome not defined. Cephalic appendages and abdomen close to each other, both positioned on short ventral margin of body. Copulatory pore present on ventrodistal surface of body, just anterior to base of abdomen. Abdomen ( Fig. 419B ) rudimentary, not articulated from prosome, unsegmented, much wider than long. Caudal rami small, not articulated from abdomen; armed with 2 (on right caudal ramus) or 4 (on left caudal ramus) setae.

Rostrum ( Fig. 419D ) stronglytapering, widerthan long, sparsely setulose along free posterior margin. Antennule ( Fig. 419E ) 2-segmented, strongly curved with expanded first segment and small second segment; armature comprising 13 setae and 1 aesthetasc on first segment, 6 setae and 1 aesthetasc on second. Antenna ( Fig. 419F ) stout, 3-segmented; coxaandbasisunarmed; unsegmented endopod twice as long as wide (34×17 μm); armedwith 4 smallsetae (2 in middle and 2 distal) plus small terminal claw, one-third as long as endopod and distinctly articulated at base.

Labrum ( Fig. 419C ) with smooth, convex posterior margin. Mandible ( Fig. 419H ) and maxillule ( Fig. 419I ) each as small lobe bearing 4 setae, some setae branched distally. Maxilla and maxilliped absent. Paired blunt tubercles ( Fig. 419G ) present lateral to oral region (indicated by arrowhead in Fig. 419C ).

Leg 1 ( Fig. 419J ) widerthan long, lamellate, directed anteriorly, unsegmented, distally bilobed; both lobes setulose; inner lobe bearing apical claw directed medially. Legs 2–5 absent.

Male. Unknown.

Remarks. Ooneides amela , the only previously known species of the genus, was initially recorded from the Mediterranean coast of France ( Chatton & Brément, 1915) and later redescribed by Illg & Dudley (1961). Ooneides californica sp. nov. differs from O. amela , as follows: (1) the body is larger, 2.29 mm long, compared to 1.0 to 1.5 mm for O. amela measured by Chatton & Brément (1915) or 1.7 mm measured by Illg & Dudley (1961); (2) the rostrum is wider than long, cf. elongate in O. amela ; (3) the mandible is a simple lobe bearing 4 setae, whereas in O. amela itis bilobed, bearing 9 ( Chatton & Brément, 1915) or more than 10 setae ( Illg & Dudley, 1961); (4) the maxillule is armed with 4 setae, compared to only 2 setae in O. amela ( Illg & Dudley, 1961); (5) the mouthparts are exposed, whereas they are surrounded by four pairs of ventral lobes as illustrated by Chatton & Brément (1915) and Illg & Dudley (1961); and (6) a prominent tubercle present on each side of the oral region in the new species, which is not present in O. amela .

Figures

FIGURE 419. Ooneides pacifica sp. nov., female. A, habitus, right, showing nauplii inside; B, urosome, ventral; C, cephalic appendages and leg 1, ventral in situ view showing position of blunt latero–oral tubercles (arrowhead); D, rostrum; E, antennule; F, antenna; G, latero–oral tubercle; H, mandible; I, maxillule; J, leg 1. Scale bars: A, 0.5 mm; B, D, F, G, J, 0.02 mm; C, 0.05 mm; E, H, I, 0.01 mm.