Campodelphys ancylocephalus, Kim & Boxshall, 2020

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 : 598-600

Campodelphys ancylocephalus gen. et sp. nov.

( Figs. 402 , 403 )

Typematerial. Holotype (intact ♀, MNHN-IU-2013- 19281 ) paratypes (2 intact ♀♀, MNHN-IU-2014-21434), and dissectedparatype (♀, figured) from a colonial ascidian, Cystodytes sp. (MNHN-IT-2008-2635 = MNHN A3/ CYS /135), Gam Island, Raja Ampat, Danau Nine Gam marine lake, West Papua, Indonesia (00°26.970’S, 130°29.149’E), depth 0.5– 2m, L.J. Bell & L.E. Martin coll., 04 November 2007.

Etymology. The specific name is the combination of Greek ancyl (=crooked) and cephal (=head), referring to the ventrally deflected cephalic region of the new species.

Descriptionoffemale. Body ( Fig. 402A ) enclosed bythin membrane; cylindricaland 1.12 mm long. Prosome 0.92 mm long, slightly narrowed in mid-section and with maximum width (250 μm) at level of leg 1, unsegmented; cephalosome not defined from metasome, directed ventrally, bearing posteroventral tubercle on each side ( Fig. 402A ). Anterior region of prosome from rostrum to insertion of leg 4 occupying 65% of prosome length; legs 1–4 separated from one another by equal intervals along body. Freeurosome ( Fig. 402B ) curved, 5-segmented. Anal somite ornamented with paired patches of spinules ventrally ( Fig. 402C ). Caudalramus ( Fig. 402C ) small, about 1.6 timeslongerthan wide (23×14 μm): armed with 6 naked setae (1 outer lateral, 1 dorsal, and 4 distal).

Rostrum ( Fig. 402D ) as longas wide, weakly tapering proximally, abruptly tapering in distal 40 % towards blunt apex. Antennule ( Fig. 402F ) small, 71 μmlong, curved posteriorly, with 2 distinct articulations proximally and several partial sutures on posterior surface more distally; armedwith 2 setaeonfirst segment, 12 on second, and 17+aesthetasc on distal region. Antenna ( Fig. 402F ) stout, taperingdistally, 3-segmented; coxaandbasisunarmed; unsegmented endopod slightly longerthan wide: armed with 1 seta distally plus terminal claw, slightly longer than endopod.

Labrum ( Fig. 402G ) large, tapering, extended distally, unornamented. Mandible ( Fig. 402H ) with coxal gnathobase bearing pectinate medial margin; palp armed with 1 setaon basis, 4 setaeon exopod, and 1 and 4 setae on first and second endopodal segments, respectively; small medial seta on second endopodal segment narrow and naked, all other setae on rami broad and weakly pinnate. Maxillule ( Fig. 402I ) lobate, bearing 6 setae (2 medial and 4 distal). Maxilla ( Fig. 402J ) indistinctly 2- segmented and armed with 5 setae on first segment and 2 setae on small second segment (medial seta markedly broadened). Maxilliped ( Fig. 402K ) unsegmented, bearing 1 smallseta subdistally on medial margin.

Legs 1–4 ( Fig. 403 A-D) biramous, broad, each with partially 2-segmented protopod, 2-segmented exopod, and unsegmented endopod; endopods much broader than exopods and directed mediodistally. Coxa of legs 1–4 unarmed, but basis bearing outer seta. Basis of leg 1 bearing spiniform innerdistal seta. All setae on rami of legs small and spiniform. Armature formula for legs 1–4 as follows:

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-1	1-0; 6	5
Leg 2	0-0	1-0	1-0; 9	6
Leg 3	0-0	1-0	1-0; 8	9
Leg 4	0-0	1-0	1-0; 7	5

Leg 5 ( Fig. 402B ) represented by 1 minute seta.

Male. Unknown.

Remarks. In Campodelphys ancylocephalus gen. et sp. nov. all swimming legs have an unsegmented endopod, unlike the three congeneric species described above. The numbers of setae on the endopods of legs 1, 2, and 4 (5, 6, and 5, respectively) are smaller than those of its congeners. The presence of 6 setae on the maxillule and 7 setae on the maxilla are additional diagnostic features of the new species.

Figures

FIGURE 402. Campodelphys ancylocephalus sp. nov., female. A, habitus, left; B, urosome, lateral; C, caudal rami, ventral; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, maxillule; J, maxilla; K, maxilliped. Scale bars: A, 0.1 mm; B–G, 0.02 mm; H–K, 0.01 mm.

FIGURE 403. Campodelphys ancylocephalus sp. nov., female. A, leg 1; B, leg 2; C, leg 3; D, leg 4. Scale bars: 0.02 mm.