Adrodelphys tectifera, 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 : 623

Adrodelphys tectifera gen. et sp. nov.

( Figs. 421 , 422 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21445 ) from Leptoclinides apertus Monniot F., 1989 (syntype MNHN-IT-2008-4769 = MNHNA2/LEP/21), Canal Woodin, Île Ouen, New Caledonia, depth 27 m, Monniot coll., 16 September 1985.

Etymology. The species name is derived from the Latin tect (=a roof) and fer (=carry), referring to the presence of a dorsal tergite on the genital somite.

Descriptionoffemale. Body ( Fig. 421A ) stout, inflated; bodylength 1.52 mm. Prosome unsegmented, 1.26 mm long, about twice as long as wide, slightly depressed, dorsoventral depth in middle 0.57 mm. In dorsal and ventral views ( Fig. 421B, D ), anterior part of prosome bearing 2 weak lateral constrictions delimiting cephalosome, firstpedigerous somite, and remaining part of prosome. Free urosome ( Fig. 421C ) small, occupying about 20% of body length, consisting of genital somite and 3 abdominal somites; defined only by weak ventral and lateral constrictions; ornamented by numerous minute spinules on ventral surface. Genital somite characteristically with dorsal tergite (indicated by arrowheads in Fig. 421A, C ). Anal somite bilobed posteriorly, incorporating caudal rami; caudal setae absent.

Rostrum ( Fig. 421E ) large, elongate, about 1.8 times longer than wide (126×71 μm), with thick wall and rounded apex. Antennule ( Fig. 421F ) small, 3-segmented; first segment broad and unarmed; second segment also broad and ornamented with many setules; thirdsegment much narrower than proximal segments, subdivided proximally, armed with several longer setules (or setae). Antenna ( Fig. 421G ) 3-segmented, moderately slender; coxaandbasisunarmed; endopod (last segment) about 2.6 times longer than wide (47×18 μm); armed with 7 smallsetae (3 in middle, 2 subdistal, and 2 distal) plus short terminal claw, about one-third as long as endopod.

Labrum small, not covering mouthparts ( Fig. 421D ). Mandible ( Fig. 421H ) unsegmented, without suture between coxa and basis; exopod and endopod also fused with basis; proximal part (coxa) bearing short, truncate gnathobase with setulose medial margin; exopod armed with 5 setae (outermost seta small, one-thirdaslongas other 4 setae); basis-endopod with 7 setae (3 medial and 4 distal). Maxillule ( Fig. 421I ) armed with 5 distinct setae on arthrite, 1 on epipodite, 2 on basis, 4 on exopod, and 3 on endopod; coxalacking endite; all setae densely pinnate, setae on exopod much larger than others. Maxilla ( Fig. 422A ) 5-segmented; syncoxa with 5 setae grouped as 1, 2, and 2 on first to third endites; basis with 1 seta only; endopod with 1, 1, and 3 setae on first to third segments, respectively; proximal seta on syncoxa and 1 seta on third endopodal segment naked, all other setae pinnate. Maxilliped ( Fig. 422B ) as small lobe bearing 2 pinnate setae apically.

Legs 1 and 2 rudimentary. Leg 1 ( Fig. 422C, D ) represented by 2 setiferous lobes; outer lobe tipped with small secondary lobe and armed with 7 setae; inner lobe smaller than outer and armed with 2 setae. Leg 2 ( Fig. 422E ) represented by small lobe bearing 2 or 3 setae and 1 isolated outer seta. Legs 3-5 absent.

Male. Unknown.

Remarks. The coxal gnathobase of the mandible has an unarmed medial margin and appears non-functional in the adult female. The morphology of the preceeding developmental stages is unknown.

Figures

FIGURE 421. Adrodelphys tectifera gen. et sp. nov., female. A, habitus, right view showing tergite on genital somite (arrowhead); B, cephalosome, dorsal; C, urosome, dorsal view showing tergite on genital somite (arrowhead); D, cephalosome and anterior pedigerous somites, ventral; E, rostrum; F, antennule; G, antenna; H, mandible; I, maxillule. Scale bars: A, 0.2 mm; B, C, 0.1 mm; D, E, 0.05 mm; F–I, 0.02 mm.

FIGURE 422. Adrodelphys tectifera gen. et sp. nov., female. A, maxilla; B, maxilliped; C, right leg 1; D, left leg 1; E, right leg 2. Scale bars: 0.02 mm.