Gallincola major, 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 : 555-558

Gallincola major gen. et sp. nov.

( Figs. 373 , 374 )

Type material. Holotype ♀ (dissected and mounted on a slide, MNHN-IU-2014-21412 ) froma gallonthebranchial tissue of Microcosmus madagascariensis Michaelsen, 1918 , the Philippines, 07 June 1905.

Etymology. The specific name refers to the larger body size of the new species comparedto the type species.

Descriptionoffemale. Body ( Fig. 373A ) similarto that of G. bisetatus gen. et sp. nov. Body length 2.90 mm. Prosome 1.95 mmlong, taperinganteriorly, unsegmented, but with 3 lateral constrictions defining cephalosome, first and second pedigerous somites and fused third and fourth pedigerous somites. Cephalosome and first pedigerous somite ( Fig. 373B ) much narrower thansecondpedigerous somite; fused thirdand fourth pedigerous somites swollen, nearly spherical, forming brood pouch. Freeurosome ( Fig. 373C ) slender, 4-segmented: genitalsomite short; 3 abdominalsomites 336×250, 273×205, and 295×159 μm, respectively. Last abdominal somite constricted at about 40% of length, marking trace of original articulation between third abdominal and anal somites; with deep posteromedial anal incision; ornamented with setules on lateral surfaces. Caudalramus ( Fig. 373D ) club-shaped, blunt, about 4.0 times longer than wide (121×30 μm), with narrow proximal part, covered with fine setules.

Rostrum ( Fig. 373E ) widerthan long, withrounded posteriormargin. Antennule ( Fig. 373E ) slender, 230 μm long, unarmed and unsegmented, but with traces of several articulations on posterior surface; anterior surface covered with fine setules. Antenna ( Fig. 373F ) 4- segmented; proximal 3 segments unarmed; last segment (secondendopodal segment) about 3.9 timeslongerthan wide (59×15 μm), ornamented with several fine setules; armedwith 5 smallsetae (arranged as 1, 2, and 2) plus small, strongly curved terminal claw.

Labrum missing. Mandible ( Fig. 373G ) with coxal gnathobase moderately broad; medial margin with 1 large distal, spiniform tooth, 2 small teeth in middle, and short proximal pectinate region: palp biramous with 1 broad, sparsely pinnate seta at mediodistal corner of basis; exopod with 5 naked setae (2 outer setae about half as long as 3 medial setae); endopod incompletely 2- segmented, with 1 broad, sparsely pinnate setaon first segment and 5 naked setae, including small outer seta, on second. Maxillule ( Fig. 373H ) with distally produced arthrite bearing 9 setae; coxa with 1 setaon epipodite, endite absent; basis with 1 naked seta on medial margin; exopod and endopod distinctly articulated from basis, exopodwith 4 pinnate setae, endopodwith 3 naked setae; middle seta distinctly longer than other 2. Maxilla ( Fig. 373I ) 4-segmented; syncoxawith 3, 1, and 2 large setae on first to third endites, respectively; basis with strong clawplus 1 large seta; endopod with 1 large setaon first segment and 2 small setae on second. Maxilliped unsegmented, elongate, armedwith 2 broad, pinnate setae distally, ornamented with scattered patches of fine setules.

Leg 1-4 ( Fig. 374 A-D) small. Legs 1–3 biramous, with widely separated rami; exopods curved and unsegmented;endopod incompletely 2-segmented inleg 1, but unsegmented, lobate inlegs 2 and 3. Leg 4 represented by elongate lobe (exopod). Protopod 2-segmented in legs 1 and 2, but unsegmented in leg 3. Rami of leg 1 and exopod of leg 2 ornamented with numerous setules. Legs lacking inner coxal and outer basal setae. Leg 1 bearing inner distal seta on basis. Setation of rami: 2, 8, 8, and 6 (or 5) on exopods of legs 1–4, respectively; 1 on second endopodal segment of leg 1, 5 or 6 on endopod of leg 2, and 1 or 2 on endopod of leg 3. Leg 5 absent.

Male. Unknown.

Remarks. Gallincola major gen. et sp. nov. can be easily distinguished from G. bisetatus gen. et sp. nov. by the following character states: (1) the caudal ramus is longer, about 4.0 timeslongerthan wide, comparedto about 2.4 times longerthan wide in G. bisetatus gen. et sp. nov.; (2) the antennule is slender and unsegmented, compared to the broad and 7-segmented antennule in G. bisetatus gen. et sp. nov.; (3) the mandibular coxal gnathobase bears 1 large and 2 small teeth, compared to 1 large and 5 small teeth in G. bisetatus gen. et sp. nov.; (4) the first endopodal segment of the mandible is armed with 2 setae, compared to only a single seta in G. bisetatus gen. et sp. nov.; (5) the setae on the basis and endopod of the maxillule are naked, whereas these setae are pinnate in G. bisetatus gen. et sp. nov.; (6) the first and second endopodal segments of the maxilla are armed with 1 and 3 setae, respectively, comparedto 2 setaeon each segment in G. bisetatus gen. et sp. nov.; and finally, (7) the exopods of legs 1–4 are unsegmented, compared to 3-segmented in G. bisetatus gen. etsp. nov.

Figures

FIGURE 373. Gallincola major gen. et sp. nov., female. A, habitus, right; B, anterior part of prosome, dorsal; C, urosome, ventral; D, right caudal ramus, dorsal; E, rostrum and antennule; F, antenna; G, mandible; H, maxillule; I, maxilla; J, maxilliped. Scale bars. A, 0.5 mm; B, C, 0.2 mm; D, E, 0.05 mm; F–J, 0.02 mm.

FIGURE 374. Gallincola major gen. et sp. nov., female. A, leg 1; B, leg 2; C, leg 3; D, leg 4. Scale bars: 0.02 mm.