Notodelphys tenera Thorell, 1859

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 : 36

Notodelphys tenera Thorell, 1859

( Fig. 19 )

Material examined. 1 ♀, 3 ♂♂ (MNHN-IU-2018- 1772) from Ascidia obliqua Alder, 1863 , middle of fjord, Kristineberg, Sweden; 1 ♀ (dissected and figured) from A. obliqua , Norway, Norbi Stn CP11, depth 300 m.

Diagnostic characters of female. Body ( Fig. 19A ) of dissected specimen 3.0 mm long. Caudal ramus ( Fig. 19B ) rectangular, about 3.6 times longer than wide (193×53 μm) and 1.4 timeslongerthan anal somite, setulose along outer margin; outer lateral seta positioned at 75% of ramus length.

Rostrum ( Fig. 19C ) tapering, about 1.5 times as long as wide, minutely bifurcate at apex. Antennule 15- segmented. Antenna ( Fig. 19D ) with 2 equally large setae on basis representing exopod; compound distal endopodal segment slender, about 5 times as long as wide; terminal claw small, about 1/3 aslongas segment.

Mandible ( Fig. 19E ) with patch of fine spinules proximally on outer surface of basis; endopod armed with 3 and 9 setae on first and second segments, respectively. Maxillule ( Fig. 19F ) with 10 setae on precoxal arthrite; endopod distinctly 2-segmented with 1 and 4 setae on first and second segments, respectively; 3 of distal setae on second endopodal segment naked. Maxilla ( Fig. 19G ) 5- segmented; syncoxalarmature elements 4, 1, 2, and 3 setae on first to fourth endites, basis with claw plus 2 setae, and with 1, 1, and 3 setae on first to third endopodal segments. Maxilliped ( Fig. 19H ) 3-segmented and armedwith 10, 1, and 3 setae on first to third segments, respectively.

Leg 1 basis with short inner distal spine less than half as long as first endopodal segment; exopod distinctly shorter than endopod; first exopodal segment with several spinules on outer margin; first endopodal segment about 1.6 times longerthan wide. Spines on outer margin of exopods of legs 2–4 slender, smooth, and straight.

Leg 5 ( Fig. 19I ) protopod distinctly articulated from ventral surface of pedigerous somite, ornamented with 4 or 5 spinules on inner distal margin, outer distal process slightly shorter than exopod and tipped with pinnate seta; free exopodal segment bulbous, narrowed proximally, about 1.7 times longerthan wide (61×37 μm), with convex outer margin and almost straight inner margin bearing 6 or 7 spinules; distal armature comprising inner spine and outer seta about as long as segment

Remarks. The characteristic shape of the free exopodal segment of leg 5 in the female allows this species to be easily identified. This species has a distribution ranging from Scandinavia in the North to the Mediterranean ( Illg, 1958).

Figures

FIGURE 19. Notodelphys tenera Thorell, 1859, female. A, habitus, right; B, anal somite and caudal rami, dorsal; C, rostrum; D, antenna; E, mandible; F, maxillule; G, maxilla; H, maxilliped; I, leg 5. Scale bars: A, 0.5 mm; B, C, 0.1 mm; D–I, 0.05 mm.