Paranotodelphys scutiformis Schellenberg, 1922

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 : 49-51

Paranotodelphys scutiformis Schellenberg, 1922 ( Figs. 31 , 32 )

Material examined. 1 ♀ (dissected) from Phallusia obesa , Vanuatu, Stn 581, Debitus coll., 1996.

Supplementary description of female. Body ( Fig. 31A ) dorsoventrally depressed, 2.09 mm long, with relatively large prosome and small urosome. Prosome withparallellateral margins.Cephalosome short, 385×618 μm, with concave posterodorsal margin. First pedigerous somiteshort, lacking epimera.Secondandthirdpedigerous somites with well-developed epimera, 138×618 and 153×611 μm, respectively. Fourthpedigerous somite forming brood pouch incorporating fifth pedigerous somite, about 1.9 times as long as wide (1171×611 μm), with rounded posterior margin. Free urosome ( Fig. 31B ) 5-segmented; somites much wider than long, 42×141, 53×124, 47×108, 44×92, and 45×82 μm, respectively. Anal somite telescoped into third abdominal somite in observed specimen; anal operculum well-developed, extending beyond posterior margin of somite ( Fig. 31C ). Caudal ramus ( Fig. 31C ) short, about 1.3 times longer than wide (45×34 μm), armedwith 6 setae (setae II and III omitted in Fig. 31C ) and ornamented with 2 dorsal setules and short, tapering tube pore (indicated by arrowhead).

Rostrum ( Fig. 31D ) directed posteriorly, tapering towards blunt apex. Large triangular tubercle present posterior to rostrum ( Fig. 31D ). Antennule slender; segmentation and setation not observed due to damage. Antenna ( Fig. 31E ) slender: coxa obscure; basiswith 2 large pinnate exopodal setae of equal length; endopod 2-segmented; first segment with 1 inner seta; compound distal segment elongate, about 5 times longer than wide, and armed with 10 setae plus terminal claw about onethirdaslongas segment.

Labrum ( Fig. 31F ) with straight posterior margin bearing setules. Mandible ( Fig. 31G ) consistingof coxa and palp: coxa with 4 teeth and 1 setaon gnathobase: palp consistingof basis, exopod and endopod; basis with setules on outer and medial margins and armed with 1 setaonmedial margin; exopodwith 5 setae, distalmost markedly larger than other 4; endopod 2-segmented and armed with 2 and 7 setae on first and second segments, respectively; suture line obscure between basis and first endopodal segment. Maxillule ( Fig. 31H ) with 10 setae on arthrite, 1 on coxal endite, 2 on epipodite, 3 onmedial margin of basis (2 small proximal and 1 larger distal), 4 on small exopod, and 5 on incompletely 2-segmented endopod (2 on first and 3 on second segment). Maxilliped ( Fig. 31J ) with 9, 0, and 2 setae on first to third segments; second segment with prominent bulbous swelling distally; third segment small, tapering, 1 seta fused with segment, lacking articulation at base.

Leg 1–4 with 3-segmented rami; coxa narrow; basis obliquely elongated. Inner coxal seta pinnate in leg 1 ( Fig. 32A ) and leg 3, but naked in leg 2 ( Fig. 32B ) and leg 4. Outer seta on basis small and naked in legs 1 and 4 but pinnate in legs 2 and 3. Armature formula as in generic diagnosis although third exopodal segment of leg 4 not observed due to damage.

Leg 5 ( Figs. 31B , 32C ) represented by 2 knobs on posterior margin of brood pouch, each tipped by naked seta, inner (exopodal) knob articulated at base.

Male. Not found.

Remarks. This is the type species of the genus ( Illg, 1958). This single female from Vanuatu is tentatively identified as P. scutiformis on the basis of the following shared characteristics: the prosome of the female has parallel lateral margins and the caudal ramus is short, only slightly longer than wide (1.25 times longer than wide, according to Schellenberg, 1922) and as long as anal somite.

Figures

FIGURE 31. Paranotodelphys scutiformis Schellenberg, 1922, female.A, habitus, dorsal; B, urosome, ventral; C, anal somite and caudal rami, dorsal; D, rostrum; E, antenna; F, labrum; G, mandible; H, maxillule; I, maxilla; J, maxilliped. Scale bars: A, 0.2 mm; B, D, E, 0.05 mm; C, F–J, 0.02 mm.

FIGURE 32. Paranotodelphys scutiformis Schellenberg, 1922, female. A, leg 1; B, leg 2; C, leg 5. Scale bars: A, B, 0.05 mm; C, 0.02 mm.