Notodelphys steinitzi Stock, 1967

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 : 37-41

Notodelphys steinitzi Stock, 1967

( Figs. 21–23 )

Material examined. 12 ♀♀, 2 ♂♂ (MNHN-IU-2018- 1774) and dissected 1 ♀, 1 ♂ (figured) from Ascidia fictile Monniot C., 1997 , Madagascar, Plante coll.; 1 ♀, 1 ♂ (MNHN-IU-2018-1775) from A. fictile, MUA 20, Nosy Be, Madagascar, Laboute coll.; 3 ♀♀, 3 ♂♂ (MNHN-IU-2018-1776) from A. fictile, MUA 20, Nosy Be, Madagascar, Laboute coll.

Supplementary description of female. Body ( Fig. 21A ) dorsoventrally depressed, 1.62 mm long. First pedigerous somite narrower than other prosomal somites: tergites of second and third pedigerous somites with angular posterolateral corners. Brood pouch wider than long, slightly narrowing distally, with weakly convex lateral margins. Freeurosome ( Fig. 21B ) consistingof genitalsomiteand 4 abdominalsomites, 45×125, 67×127, 58×127, 51×127, and 45×127 μm, repectively; lateral margins of abdomen parallel. Caudal ramus about 1.7 times as long as wide (91×55 μm), rectangular, surface covered by dense ornamentation of transparent scales and thin setules; armed with 6 pinnate setae, all located distally.

Rostrum ( Fig. 21C ) tapering, longerthanwide, with truncate, slightly concave distal margin bearing spinulose lobe. Antennule ( Fig. 21D ) slender, longerthan cephalosome, 15-segmented; armatureformula 3, 6, 12, 6, 4, 2, 2, 2, 1, 1+aesthetasc, 1, 1, 2, 2, and 7+aesthetasc; most of setae on proximal 5 segments pinnate, other setae on distal segments naked (as figured). Antenna ( Fig. 21E ) slender, with short, obscure coxa; basiswith long pinnate seta and short naked setae representing exopod; first endopodal segment slightly shorter than basis, with 1 seta subdistally on inner margin and fine spinules on outer margin; compound distal endopodal segment elongate, about 7.6 times as long as wide (174×23 μm), ornamented with longitudinal row of minute spinules along outer margin: armed with small terminal claw and 11 setae (grouped as 1, 1, 3, 1, 2, and 3), distal 3 of which claw-like, pointed at tip.

Labrum ( Fig. 21F ) narrowing distally, setulose along posterior margin, with indistinct posteromedian lobe bearing fine spinules. Mandible ( Fig. 21G ) with 5 teeth (distal 2 acutely pointed) and 2 proximal setae on coxal gnathobase; basiswith 1 setaonmedial margin; exopod 2-segmented with 1 and 4 setae on first and second segments, respectively, distalmost seta distinctly longer than others; endopod with 2 and 9 setae on first and second segments, respectively; first endopodal segment ornamented with spinules on medial margin. Maxillule ( Fig. 21H ) armedwith 10 setaeon arthrite, 1 setaon coxal endite, 2 setaeon epipodite, and 3 setae (proximal one smaller) on medial margin of basis; exopod with 4 setae, all apparently united at base; endopod incompletely 2-segmented and armed with 1 and 4 setae on first and second segments, respectively, 3 distal setae longer and naked. Maxilla ( Fig. 22A ) 5-segmented; syncoxawith 9 enditic setae, arranged as 3, 1, 2, and 3; basis with long, strongly arched claw plus 2 setae; endopod with 1, 1, and 3 setaeon firsttothird segments, respectively. Maxilliped ( Fig. 22B ) 3-segmented and armed with 9, 1, and 3 setae on first to third segments, respectively.

Legs 1–4 biramous with 3-segmented rami ( Fig. 22 C–E). Inner seta on coxa and outer seta on basis pinnate in legs 1–3 but naked in leg 4 ( Fig. 22E ). Number of armature elements as usual for genus, but exopod of leg 4 armed only with setiform elements. Inner distal spine on basis of leg 1 straight, narrow, and as long as first endopodal segment.

Leg 5 ( Fig. 22F ) 2-segmented; protopod broad but short, with smooth, tapering outer distal process tipped with 1 naked seta; exopod about 1.2 times longer than wide (22×19 μm), distinctly shorter than outer distal process of protopod, with narrow base, convex outer margin, and armed with shorter inner margin seta and longer distal seta, both setae naked.

Supplementarydescriptionofmale. Body ( Fig. 23A ) narrowerthan female, 916 μm long. Tergites of second to fourth pedigerous somites with rounded posterolateral corners. Urosome ( Fig. 23B ) 6-segmented: fifth pedigerous somite free, 132 μm wide; genital and 4 abdominalsomites 64×121, 45×112, 38×105, 35×100, and 36×97 μm, respectively. First abdominal somite ornamented with transverse row of spinules in middle of ventral surface. Caudal ramus about 1.7 times as long as wide (73×42 μm), armed and ornamented as in female.

Rostrum asin female. Antennule ( Fig. 23C ) 11- segmented, segmental fusion pattern: I-II, III-V, VI-XI, XII, XIII, XIV, XV-XVII, XVIII, XIX-XX, XXI-XXIII, XXIV-XXVIII: geniculate between ninth ( XIX-XX) and tenth ( XXI-XXIII) segments; armature 3, 5, 12, 2, 2, 2, 5, 2, 2+aesthetasc, 2+aesthetasc, and 10+aesthetasc; nearly all setae naked. Antenna, mouthparts, and legs 1–4 as in female.

Leg 5 ( Fig. 23D ) represented by 1 seta on posterolateral corner of fifth pedigerous somite and free exopodal segment, 18×16 μm, shaped as in female. Leg 6 ( Fig. 56D ) represented by 2 equal, naked setae and 1 minute, inner spinule on posterior margin of genital operculum.

Remarks. Stock (1967) described this species as an associate of Phallusia nigra Savigny, 1816 (as Ascidia nigra ) collected on the Red Sea coast in the Dahlak Archipelagoandinthe Sheikh Said Channel near Massawa, Ethiopia. Most of the features given in his description are confirmed from our specimens except the plumosity of some of the setae on certain appendages. The dense covering of transparent scales on the caudal rami was overlooked by Stock (1967). Ascidia fictile is a new host record for this copepod and its discovery in Madagascan waters represents a significant extension of its known range along the Indian Ocean coast of East Africa.

Figures

FIGURE 21. Notodelphys steinitzi Stock, 1967, female. A, habitus, dorsal; B, urosome, ventral; C, rostrum; D, antennule; E, antenna; F, labrum; G, mandible; H, maxillule. Scale bars: A, 0.2 mm; B–G, 0.05 mm; H, 0.02 mm.

FIGURE 22. Notodelphys steinitzi Stock, 1967, female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, leg 4; F, leg 5. Scale bars: A, B, F, 0.02 mm; C–E, 0.05 mm.

FIGURE 23. Notodelphys steinitzi Stock, 1967, male. A, habitus, dorsal; B, urosome, ventral; C, antennule; D, legs 5 and 6. Scale bars: A, 0.1 mm; B, C, 0.05 mm; D, 0.02 mm.

FIGURE 56. Notodelphyopsis gemina sp. nov., female.A, antenna; B, maxilla; C, maxilliped; D, leg 1; E, leg 2; F, leg 4; G, leg 5. Scale bars: A, D–F, 0.05 mm; B, C, G, 0.02 mm.