Notodelphys parva 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 : 36

Notodelphys parva Schellenberg, 1922

( Fig. 20 )

Material examined. 3 ♀♀, 1 ♂ (MNHN-IU-2018-1773) and 2 dissected ♀♀ from Herdmania momus (Savigny, 1816) , Ibo P. 5, coral reef, Mozambique, 10 November 1995.

Diagnostic characters of female. Body ( Fig. 20A ) dorsoventrally depressed, 1.47 mm long. Brood pouch sub-quadrate, longerthan wide. Freeurosome short, 5- segmented. Caudalramus rectangular, about 1.9 times longer than wide (125×65 μm), densely covered with transparent scales on dorsal and ventral surfaces (scales not illustrated on Fig. 20A ), setulose along inner and outer margins; armed with 6 setae, all located distally.

Antennule 15-segmented. Antenna with exopod represented by 2 subequal setae; compound distal endopodal segment extremely elongate, about 10 times longerthanwide (191×19 μm).

Mandibular gnathobase with 5 teeth, second distal tooth tri- or quadricuspidate; exopod armed with 5 setae and endopod with 2 and 9 setae on first and second endopodal segments, respectively. Maxillule as usual for genus; with 10 setae on precoxal arthrite, 3 setaeon medial margin of basis, and 5 setae on unsegmented endopod. Maxilla typical for genus, with 3 setae on first endite of syncoxa and 1, 1, and 3 setae on first to third endopodal segments, respectively. Maxilliped with 9, 1, and 3 setae on first to third segments, respectively.

Inner distal spine of basis of leg 1 smooth and as long as first endopodal segment. Legs 2 ( Fig. 20B ) and 3 unusual in having 2 spines and 7 setae on third exopodal segment; almost all setae on these legs with defined breaking plane at proximal quarter, except outer subdistal seta. Leg 5 ( Fig. 20C ) protopod with broad, tapering outer distal process tipped with naked seta; free exopodal segment slightly longer than wide (26×20 μm), with roundly protruded outer margin and 2 unequal, naked setae.

Remarks. The presence of 2 spines and 7 setae, rather than the typical 4 spines and 5 setae as usual, on the third exopodal segment of both legs 2 and 3 is the most characteristic feature of this species. The dense ornamentation of transparent scales on the caudal rami of N. parva is also found in N. steinitzi Stock, 1967 and Stock (1967) provided detailed comparisons between these two species.

This species was originally described from the Gulf of Suez living in association with Herdmania momus (as Pyura momus ) and Polycarpa ehrenbergi Hartmeyer, 1916 ( Schellenberg, 1922) . Subsequently, Stock (1967) recorded N. parva from Herdmania momus , an unidentified species of the family Pyuridae , and from Didemnum candidum Savigny, 1816 collected in the Red Sea.

Figures

FIGURE 20. Notodelphys parva Schellenberg, 1922, female. A, habitus, dorsal; B, leg 2; C, leg 5. Scale bars: A, 0.2 mm; B, C, 0.05 mm.