Loboixys pilosa, 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 : 530-533

Loboixys pilosa sp. nov.

( Fig. 353 , 354 )

Typematerial. Holotype (intact ♀, MNHN-IU-2014- 21397 ) , paratypes (2 intact ♀♀, MNHN-IU-2014-21398), and dissected paratypes (2 ♀♀, figured) from Diplosoma multifidum (Sluiter, 1909) , Récif Néokumbi, New Caledonia, depth 40 m, Monniot coll., 10 March 1987.

Additionalmaterial. 6 ♀♀ (MNHN-IU-2018-1909) embedded in tissues of D. multifidum, Îlot Atire, NC 63, New Caledonia, 1987; 1 ♀ (MNHN-IU-2018-1910) from D. multifidum, NC 30, New Caledonia, 09 March 1987.

Etymology. The name is derived from the Latin pilos (=hairy) and refers to the hairy body surface of the new species.

Descriptionoffemale. Body ( Fig. 353A, B ) very similar in form to Loboixys sibogae sp. nov., 1.39 mm long. Prosome 5-segmented: dorsal cephalic shield bearing paired minute horn-like processes posterolaterally ( Fig. 353D ); surface of dorsal cephalic shield and anterior 3 pedigerous somites covered with numerous fine setules. Fourth pedigerous somite forming almost spherical brood pouch, about 970 μm long, longer than anterior part of prosome. Free urosome ( Fig. 353C ) inserted into anterior ventral surface of brood pouch, 5-segmented: genital somite 58×182 μm; 4 abdominal somites covered with fine setules, 56×156, 51×138, 38×125, and 62×124 μm, respectively. Caudal rami broad, about 1.7 times longer than wide (93×56 μm) and 1.5 times longerthan anal somite, covered with fine setules, tapering with straight lateral margin and continuously curved inner and distal margins: armed only with 3 small distal setae.

Rostrum ( Fig. 353E ) aslongas wide, nearly semicircular, with slight lateral constriction proximally; setulose in distal third. Antennule ( Fig. 353F ) strongly tapering, setulose, about 120 μmlong, 5-segmented; first and second segments much wider than distal segments; armature formula 1, 5, 2, 2, and 3; setae indistinguishable from setules. Antenna ( Fig. 353G ) 3-segmented; coxa and basis unarmed; slender endopod 4.1 times longer than wide (73×18 μm), slightly shorter than basis: armed with 6 setae (grouped as 1, 2, and 3) plus small terminal claw, aboutone-thirdaslongas endopod.

Labrum ( Fig. 353H ) broadly inflated distally, setulose and soft. Mandible ( Fig. 353I ) with medially broadened coxal gnathobase bearing 5 acute teeth and 1 seta: basiswith 1 setaonmedial margin: exopodwith 5 subequal setae; endopod with 1 seta on first segment and 4 setaeon second. Maxillule ( Fig. 353J ) with 8 setae on arthrite, 1 each on epipodite and basis, 4 on exopod and 3 on endopod; coxal endite absent. Maxilla ( Fig. 354A ) 4-segmented; syncoxa with 4, 2, and 2 on first to third endites, respectively; basis with small claw plus 2 unequal setae; endopod with 1 and 3 setae on first and second segments, respectively; setaon first endopodal segment and one setaon second thick. Maxilliped ( Fig. 354B ) unsegmented, but constricted in middle, armed with 6 setae and ornamented with 4 rows of setules.

Legs 1–4 ( Fig. 354 C-F) biramous with 2-segmented protopods. Inner coxal seta absent in all legs. Leg 1 with innerdistal setaon basis. Exopod 2-segmented in leg 1 and incompletely 3-segmented inlegs 2–4. Endopod 3- segmented inleg 2 and 2-segmented inlegs 1, 3, and 4. Both rami of legs 1–4 ornamented with setules in addition to setae. Setaeon all swimming legs short. First exopodal segment of legs 2–4 lacking inner seta. Outer seta on basis and 3 inner setae on exopod of leg 1 weakly pinnate; all other setae on legs 1–4 naked. Armature formula for legs 1–4 as follows:

	Coxa	Basis	Exopod	Endopod
Leg 1	0-0	1-I	1-1; 1, 1, 5	0-1; 1, 2, 4
Leg 2	0-0	1-0	1-0; 1-1; 3, 1, 5	0-1; 0-1; 1, 2, 3
Leg 3	0-0	1-0	1-0; 1-1; 3, 1, 5	0-1; 1, 2, 4
Leg 4	0-0	1-0	1-0; 1-1; 2, 1, 5	0-1; 1, 2, 3

Leg 5 ( Fig. 354G ) bilobed; outer (protopodal) lobe digitiform, and tipped with 1 seta; inner (exopodal) lobe broad, bearing 1 smallseta distally and acutely pointed, hook-like process mediodistally.

Male. Unknown.

Remarks. Leg 5 of Loboixys pilosa sp. nov. consists of an elongate outer lobe bearing the protopodal seta and an inner lobe representing the exopod, which carries a hook-like distal process. This form of leg 5 is the most distinctive feature of L. pilosa sp. nov., because it is unique within the genus. Other diagnostic features of the new species include: the presence of a claw plus 2 setae on the basis of the maxilla, and the endopods of legs 2 and 3 are armed with 8 setae each (compared to at most 7 setae as in L. ryukyuensis and L. sibogae sp. nov.).

Within the genus only two species, L. pilosa sp. nov. and L. capillosus ( Ho & Kim, 2009) comb. nov. have a claw on the basis of the maxilla, but these two species can be easily separated because L. capillosus has a different form of leg 5 and has fewer setae on the rami of legs 2– 4.

Figures

FIGURE 353. Loboixys pilosa sp. nov., female. A, habitus, dorsal; B, habitus, right; C, leg 5 and urosome, ventral; D, cephalosome, right; E, rostrum; F, antennule; G, antenna; H, labrum; I, mandible; J, maxillule. Scale bars: A, B, 0.2 mm; C, E, 0.05 mm; D, 0.1 mm; F–J, 0.02 mm.

FIGURE 354. Loboixys pilosa sp. nov., female. A, maxilla; B, maxilliped; C, leg 1; D, leg 2; E, lef 3; F, leg 4; G, leg 5. Scale bars: 0.02 mm.