Campodelphys stocki, 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 : 595-598

Campodelphys stocki gen. et sp. nov.

( Figs. 400 , 401 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014-21432 ) , paratype (intact ♀, MNHN-IU-2014-21433), and dissected paratype (♀, figured) from Eudistoma vulgare Monniot F., 1988 (MNHN-IT-2008-4307 = MNHNA 3/ EUD /58), Grand récif Sud New Caledonia, “Vauban”, (22°36.3’S, 167°14.2’E), depth 20-60m, B. Richer de Forges-IRD coll., 24 January 1985.

Etymology. The new species is named in honour of the late Prof. Jan H. Stock for his many contributions to the taxonomy of ascidicolous copepods.

Descriptionoffemale. Body ( Fig. 400A ) elongate, cylindrical, archedventrally: bodylength 1.78 mm. Prosome unsegmented and evenly cylindrical (width 320 μm) along most of length; cephalosome tapering anteriorly, not articulated from metasome, narrower than metasome, withprominentposteroventral tubercle oneach side ( Fig. 400D ). Anterior region from rostrum to level of leg 4 occupying about one-third of prosome length. Free urosome ( Fig. 400B, C ) small, 122 μmlong, 5 urosomites each markedly wider than long. Anal somite ornamented with 2 oblique rows of spinules on ventral surface near bases of caudal rami ( Fig. 400E ). Caudal ramus small, about 2.4 timeslongerthan wide (38×16 μm), obscurely defined from anal somite: armed with 6 equal, naked setae (2 in middle and 4 distal).

Rostrum ( Fig. 400F ) elongate, about twice as long as wide, with slightly convex lateral margins bearing pair of setules distally; distal third narrowing towards apex. Antennule ( Fig. 400G ) small, 82 μmlong, tapering, and curved posteriorly; segmentation obscure with 6 partial sutures along posterior surface; setae grouped as 2, 21, 6, and 13. Antenna ( Fig. 400H ) very stout, 3-segmented; coxa short; basis slightly longerthan wide, unarmed; unsegmented endopod as long as wide: armed with 5 small setae (1 middle, 1 subdistal, and 3 distal) plusterminal claw, slightly longer than endopod.

Labrum ( Fig. 400I ) extending posteriorly, tapering, as long as wide, with 2 large setules subdistally. Mandible ( Fig. 400J ): coxal gnathobase with pectinate medial margin plus 1 small spinule on distal margin; palp armed with 1 setaon basis, 4 setaeon exopod, and 1 and 4 setae on first and second endopodal segments, respectively; both rami incompletely articulated from basis; all setae naked. Maxillule ( Fig. 401A ) lobate, bearing 7 naked setae (3 mediodistal setae smaller than remaining 4). Maxilla ( Fig. 401B ) lobate, armedwith 7 pinnate setae (4 medial and 3 distal). Maxilliped ( Fig. 401C ) small, 2-segmented, bearing 2 small setae on medial margin of secondsegment.

Legs 1–4 ( Fig. 401 D-G) shortand broad; protopods indistinctly 2-segmented; exopods 2-segmented, obscurely defined from basis; endopod 2-segmented inleg 1, unsegmented in legs 2–4, although retaining vestige of articulation. Basis of leg 1 bearing broad, spiniform inner distal seta. Coxa and basis unarmed in legs 2–4. Setae on rami short, broad, naked, usually blunt tipped. Armature formula for legs 1–4 as follows:

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

Leg 5 ( Fig. 400B ) represented by 2 small posteroventral setae at rear of prosome near base of free urosome.

Male. Unknown.

Remarks. In Campodelphys stocki gen. et sp. nov. the endopod is 2-segmented in leg 1, but 1-segmented in legs 2–4. This leg segmentation pattern is unique and serves to differentiate the new species from all of its congeners. The 2-segmented maxilliped bearing two setae on the second segment and the presence of 7 setae on both the maxillule and maxilla also are characteristic features of the new species, as this combination does not occur in any other species.

Figures

FIGURE 400. Campodelphys stocki sp. nov., female. A, habitus, right; B, urosome, ventral; C, urosome, right; D, cephalosome and leg 1, ventral; E, caudal rami; F, rostrum; G, antennule; H, antenna; I, labrum; J, mandible. Scale bars: A, 0.2 mm; B–E, 0.05 mm; E–J, 0.02 mm.

FIGURE 401. Campodelphys stocki sp. nov., female. A, maxillule; B, maxilla; C, maxilliped; D, leg 1; E, leg 2; F, leg 3; G, leg 4. Scale bars: 0.01 mm.