Notodelphys elegans 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 : 31-32

Notodelphys elegans Thorell, 1859

( Fig. 16 )

Material examined. 11 ♀♀, 7 ♂♂ (MNHN-IU-2018- 1768) and 1 dissected ♀ (figured) from Ciona intestinalis (Linnaeus, 1758) , Adriatic Sea.

Diagnostic characters of female. Body ( Fig. 16A ) of dissected female 2.50 mm long. Caudal rami ( Fig. 16B ) widely separated from one another, about 2.9 times longer than wide (132×45 μm) and about 1.1 timeslongerthan anal somite (118×145 μm), and setulose on both outer and inner margins; outer lateral seta located at 67% of ramus length.Rostrumlongerthanwide, taperingtowardsangular apex. Antennule 15-segmented. Antenna rather stout with 2 equal exopodal setae; compound distal endopodal segment about 3 timeslongerthan wide. Mandibular endopod with 3 and 9 setae on first and second segments, respectively. Maxillule indistinctly 2-segmented with 1 and 4 setae on first and second segments, respectively. Maxilla 5-segmented; syncoxawith 4, 1, 2, and 3 setaeon first to fourth endites, respectively; basis with claw plus 2 setae; endopod 3-segmentedwith 1, 1, and 4 setaeonfirst to third segments, respectively. Maxilliped with 10, 1, and 3 setae on first to third segments, respectively. Legs 1–4 as typical for genus. Leg 5 ( Fig. 16C ) protopod with about 15 spinules scattered irregularly along inner margin and with elongate outer extension bearing plumose seta at tip and 1 subdistal tooth on inner margin; exopodal segment subcircular, about 1.3 times as long as wide (32×25 μm), armedwith 1 spineand 1 plumose seta; ornamented with 1 denticle distally on outer margin and 3 spinules on inner margin near base of spine.

Remarks. As Sars (1921) noted, the caudal ramus is about 3 times longer than wide and only slightly longer than the anal somite, and the outerlateral seta on the ramus is positioned subdistally. In addition, the protopod of leg 5 has an elongate digitiform outer process and distinctly spiniferous inner margin, and the exopodal segment is suboval with a strong inner spine. These characteristic features of N. elegans are present in our material from the Adriatic Sea. The species was originally reported from Swedish waters ( Thorell, 1859) and its known distribution extends from Scandinavia, along the coast of northwestern Europe and into the Mediterranean ( Illg, 1958; Illg & Dudley, 1961).

Figures

FIGURE 16. Notodelphys elegans Thorell, 1859, female. A, habitus, right; B, anal somite and caudal rami, dorsal; C, leg 5. Scale bars: A, 0.5 mm; B, 0.05 mm; C, 0.02 mm.