Gallincola bisetatus, 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 : 555

Gallincola bisetatus gen. et sp. nov.

( Figs. 371 , 372 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21411 ) from a discoid gall formed on the branchial tissue of the ascidian Pyura gangelion (Savigny, 1816) (MNHN-IT-2008-7540 = MNHNS2/ PUY/143), KARUBAR DW31, Iles Kai, N/O “ Baruna Jaya 1 ”, Indonesia (05°40’S, 132°51’E), depth 288-289 m, Bouchet, Kastoro & Métivier coll., 26 October 1991.

Etymology. The specific name is derived from the Latin bi (=two) and set (=seta), alluding to the presence of two setaeon the first endopodal segment of the mandible.

Description of female. Body ( Fig. 371A ) with thin, soft epidermis; bodylength 2.22 mm. Prosome distinctly tapering anteriorly; dorsal cephalic shield expanded ventrally, lacking posterolateral processes. Cephalosome and first pedigerous somite incompletely articulated from each other and from remaining part of prosome ( Fig. 371B ); second to fourth pedigerous somites not articulated. Region of fourth pedigerous somite swollen forming almost spherical brood pouch. Fifth pedigerous somite not defined. Free urosome ( Fig. 371C ) 4-segmented, slender, consistingof genital somite and 3-segmented abdomen. Genital somite short, notarticulated from brood pouch; 3 abdominal somites 140×170, 126×140, and 210×120 μm, respectively. Last abdominal somite longer than others, probably formed by fusion of original third abdominal and anal somites, with deep posteromedian (anal) incision, and ornamented with numerous surface setules. Caudal rami ( Fig. 68D ) directed posterolaterally, about 2.4 timeslongerthan wide (63×26 μm) with rounded apex, distinctly articulated at base, covered with numerous setules; lacking setae.

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-1	1-1; 1-1; 6	0-1; 0-1; 5
Leg 2	0-0	1-0	1-0; 1-0; 8	0-0; 3 or 4
Leg 3	0-0	1-0	1-0; 1-0; 8	0-0; 1
Leg 4	0-0	1-0	1-0; 1-0; 5	0-0; 0
Leg 5	absent.

Rostrum ( Fig. 371E ) with evenly convex distal margin, setulose, and not articulated at base. Antennule ( Fig. 371F ) broad, graduallynarrowing distally and slightly curved posteriorly, about 170 μm long, and 7- segmented; articulations between third and terminal segments incomplete; armatureformula 3, 5, 3, 1, 2, 2, and 12; setae small; second to terminal segments ornamented with setules on anterior surface. Antenna ( Fig. 371G ) moderately slender, 4-segmented; coxa, basis and first endopodal segment unarmed, almost equal in length; second endopodal segment about 3.6 times longer than wide (69×19 μm) and aslongas first: armedwith 4 small setae (2 inserted into base of terminal claw) and several setules; terminal claw small, about one-third as long as secondendopodal segment.

Labrum ( Fig. 372A ) with smooth, convex posterior marginand patches of fine spinules posterolaterally. Mandible ( Fig. 371H ) with broad coxal gnathobase; medial margin of gnathobase with 1 elongate distal tooth, 5 unequal, smaller teeth in middle, proximal pectinate region, and 2 small setae on proximal corner: palp consistingof basisbearing 1 small setaat mediodistal corner, 4 large setae and 1 smallseta on exopod (small outer seta one-third as long as larger setae), 2 unequal setae on first endopodal segment, and 5 setae on second; all setae pinnate. Maxillule ( Fig. 371I ) with 9 setae (including 1 small naked seta) on large, pronounced arthrite, 1 each on epipodite and basis, 4 on exopod and 3 on endopod; coxal endite absent; exopod and endopod small; exopod not articulated from basis; all setae on rami pinnate. Maxilla ( Fig. 372B ) consistingof syncoxa, basis, and 2-segmented endopod; syncoxawith 3, 1, and 2 setae on first to third endites, respectively; basis with smooth clawplus 1 seta; endopod small with 1 and 3 setaeon firstandsecondsegments, respectively. Maxilliped ( Fig. 372C ) unsegmented, tapering apically, armedwith 2 or 3 setae (outer subdistal seta indicated by arrowhead in Fig. 372C may be present or absent) and ornamented with setules on all surfaces.

Legs 1–4 ( Fig. 372 D-H) small, biramous; protopod unsegmented or indistinctly 2-segmented; coxa lacking inner seta. Basis of legs 1–4 with outer seta. Basis of leg 1 with innerdistal seta. Exopods 3-segmented, densely setulose in leg 1, but with few setules in legs 2–4. Endopods much smaller than exopods, 3-segmented in leg 1, and 2-segmented in legs 2–4. Endopods of legs 3 and 4 vestigial. All setae on legs small and naked. Armature formula for legs 1–4 as follows.

Male. Unknown.

Remarks. Thegall fromwhich the copepodspecimen was removed was discoid and formed from membranous host tissue on the surface of the branchial wall.

Figures

FIGURE 68. Pachypygus gibber (Thorell, 1859), female. A, habitus, right; B, urosome, ventral; C, distal part of abdomen, right; D, distal part of abdomen, dorsal; E, distal part of abdomen, ventral; F, caudal ramus, lateral; G, rostrum; H, antennule; I, antenna; J, labrum. Scale bars: A, 1 mm; B, 0.5 mm; C–F, H–J, 0.01 mm; G, 0.02 mm.

FIGURE 371. Gallincola bisetatus gen. et sp. nov., female. A, habitus, right; B, cephalosome and first pedigerous somite, dorsal; C, urosome, dorsal; D, caudal rami, dorsal; E, rostrum; F, antennule; G, antenna; H, mandible; I, maxillule. Scale bars: A, 0.2 mm; B, C, 0.1 mm; D, E, 0.05 mm; F–I, 0.02 mm.

FIGURE 372. Gallincola bisetatus gen. et sp. nov., female. A, labrum, B, maxilla; C, maxilliped (marked seta absent in some specimens); D, leg 1; E, F, leg 2; G, leg 3; H, leg 4. Scale bars: A, 0.05 mm; B–H, 0.02 mm.