Hamaticoxa nuda, 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 : 621

Hamaticoxa nuda gen. et sp. nov.

( Fig. 420 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21444 ) from Distaplia sp., Red Sea coast of Israel, 1962.

Etymology. The name is derived from the Latin nud (=naked), and alludes to the unornamented body surface of the new species.

Description of female. Body vermiform, cylindrical, consistingof cephalosomeandelongatetrunk ( Fig. 420A ); body surface smooth without ornamentation of setules or spinules. Cephalosome nearly rectangular, widerthan long, slightly narrower than trunk, defined from trunk by lateral constriction, with truncate frontal margin. Trunk unsegmented, gradually narrowing posteriorly towards bilobed posterior margin incorporating paired caudal rami on either side of anal slit ( Fig. 420B ). Caudal rami fully fused to trunk; represented only by 6 caudal setae on tip of each posterior lobe of trunk ( Fig. 420C ). Paired spermatophores attached laterally near middle of trunk ( Fig. 420A ), each ( Fig. 420D ) 123×55 μm, with thick wall.

Rostrum ( Fig. 420E, F ) large, about twice as long as wide, withrounded apex. Antennule ( Fig. 420I ) small, strongly tapering, aslongas wide, unsegmented, but with 3 partial suture lines on posterior surface; armed with more than 10 minute setae, most positioned distally. Antenna ( Fig. 420G ) stout, 3-segmented, consistingof broad, unarmed coxa and basis, and narrow unsegmented endopod about 2.1 timeslongerthan wide (97×46 μm); armed with 9 minute setae (3 middle, 2 subdistal, and 4 distal) plus small terminal claw ( Fig. 420H ), one-third as long as endopod, and articulated from endopod.

Labrum simple with straight posterior margin. Mandible ( Fig. 420J, K ) consistingof coxa and small, unsegmented palp; coxal gnathobase transformed to powerful, strongly curved hook, lacking armature or ornamentation; palp tapering, much shorter than coxal hook, armed with 4 small setae (2 subdistal and 2 distal). Maxillule ( Fig. 420L ) elongate, unsegmented, bearing 4 broad naked setae (1 proximal, 2 subdistal, and 1 distal). Maxilla ( Fig. 420M ) indistinctly 3-segmented and armed with 6 large and 2 small setae: 1 on first segment, 2 on second, and 5 on third (2 distal setae small); some of large setae feebly pinnate, others naked. Maxilliped absent. Legs 1–5 absent.

Male. Unknown.

Remarks. Apair of spermatophores was found attached in the middle of the trunk, not immediately adjacent to the more posteriorly located copulatory pore.

Figures

FIGURE 420. Hamaticoxa nuda gen. et sp. nov., female. A, habitus, dorsal; B, posterior part of trunk, ventral; C, caudal setae; D, spermatophore; E, cephalosome, oblique ventral; F, rostrum (damaged); G, antenna; H, distal part of antenna; I, antennule; J, K, mandibles; L, maxillule; M, maxilla. Scale bars: A, 1 mm; B, E, F, 0.1 mm; C, D, G, 0.05 mm; H–M, 0.02 mm.