Caligus fistulariae Yamaguti, 1936

Moon, S. - Y. & Kim, I. - H., 2012, Sea lice (Copepoda, Siphonostomatoida, Caligidae) new to Korea, including three new species, Journal of Species Research 1 (2), pp. 175-217 : 181-184

Caligus fistulariae Yamaguti, 1936

( Figs. 5 , 6) Caligus fistulariae Yamaguti, 1936, p. 3 , pl. 2, figs. 14-

26; Shiino, 1964, p. 243, figs. 1, 2; Fernández and

Villalba, 1986, p. 45; Ho et al., 2008, p. 88, figs. 1-3.

Material examined. 2¥¥, 1J from mouth tube of Fistularia commersonii Ruppell , at Sagye in Jeju Island, M.-K. Choe, 29 October 2009 .

Female. Body ( Fig. 5A ) large, 6.86 mm long. Cephalothoracic shield 3.13× 2.44 mm, distinctly longer than wide; lateral zone with smoothly curved ventral rib; posterior sinus deep; posterolateral pit present. Fourth pedigerous somite indistinctly articulated from genital complex. Genital complex gradually broadened distally, 2.30 × 1.92 mm, with rounded and slightly projected posterolateral corners. Abdomen 1-segmented, 0.90× 0.67 mm, with convex lateral margins. Caudal ramus 335×219 µm, 1.53 times as long as wide, with 6 setae; inner margin convex, with setules on distal half ( Fig. 5B ).

Antennule ( Fig. 5C ) 558 µm long and 2-segmented; proximal segment occupying 65% length of antennule, with 27 pinnate and 2 naked setae; distal segment with 12 naked setae and 2 aesthetascs. Antenna 3-segmented; first segment without proximal process ( Fig. 5D ); second segment nearly quadrangular, with 1 adhesion pad; third segment forming long, distally strongly bent claw bearing 2 small setae. Postantennal process proximally bearing 2 papillae each tipped with 1 setule; another papilla located posterior to postantennal process also tipped with 1 setule.

Mandible with 12 teeth distally. Maxillule consisting of anterior papilla bearing 3 unequal setae and tapering posterior process ( Fig. 5D ). Maxilla ( Fig. 5E ) 2-segment- ed; proximal segment (lacertus) unarmed; slender distal segment (brachium) with membrane (flabellum) at about 70% region of inner margin; calamus about twice as long as canna. Maxilliped ( Fig. 5F ) 3-segmented; first segment (corpus) with broader proximal half and narrower distal half; second segment (shaft) 1 seta and 1 small denticle distally; third segment forming short, curved claw. Sternal furca ( Fig. 5G ) with slender, tapering tines bearing blunt tip.

Armature on rami of legs 1-4 as follows:

Leg 1: exopod 1-0; 3,1,3; endopod (vestigial)

Leg 2: exopod I-1; I-1; II,I,5; endopod 0-1; 0-2; 6

Leg 3: exopod I-0; I-1; III,4; endopod 0-1; 6

Leg 4: exopod I-0; III; endopod (lacking)

Leg 1 ( Fig. 5H ) coxa with simple outer setule; basis with pinnate outer and inner setae. Proximal exopodal segment with 1 small outer distal naked seta and row of setules on inner margin; distal segment with relatively short outermost seta; two mid-terminal setae with short setules; inner distal seta naked and longer than mid-terminal setae; endopod small, knob-like. Leg 2 ( Fig. 6A) coxa with large seta on inner posterior margin; basis with small outer seta and 1 inner setule and membrane on inner part of posterior margin; outer side of basis and first exopodal segment with broad membrane (not illustrated in Fig. 6A). Leg 3 ( Fig. 6B) protopod broad membrane on outer and inner margins; outer spines on second and third segments setiform. Leg 4 ( Fig. 6C) protopod with convex outer margin; spines on first exopodal segment 166 µm; three spines on terminal segment 131, 188, and 246 µm from outer to inner; all spines on exopodal segments accompanied with flabella near base. Leg 5 represented by 1 and 2 small setae on posterolateral margin of genital complex.

A B C E D F H G

Male. Body ( Fig. 6D) 4.10 mm long. Cephalic shield resembling that of female, 2.29× 1.83 mm. Genital complex 769×638 µm. Abdomen 2-segmented; proximal segment 169×315 µm; distal segment 323×392 µm. Caudal ramus 269×185 µm.

Antennule as in female. Antenna ( Fig. 6G) 3-segment- ed as in female; first segment with 2 weak adhesion pads; second segment with 4 adhesion pads; third segment blunt, with 1 inner proximal setae and forming foliaceous. Postantennal process ( Fig. 6F) larger than that of female.

Mandible, maxillule, and maxilla as in female. Maxilliped ( Fig. 6H) with protruded inner margin of first segment; claw short, stout, almost fused with second segment. Sternal furca similar to that of female.

Legs 1-5 as in female. Leg 6 represented by 2 small setae on each genital flap.

Distribution and hosts. Japan, Taiwan, Korea, and Chile. Known hosts are Fistularia petimba Lacepède , F. villosa Kluzinger , F. commersonii Ruppell , and Aulostomus chinensis (Linnaeus) .

Remarks. The form and relative size of the four terminal elements of leg 1 exopod and the shape of the three apical spines of leg 4 show some differences between the illustrations of Ho et al. (2008) and our specimens, which are thought to be artifacts. The larger body size and the characteristic shape of the sternal furca and maxilliped are shared by specimens from both countries.

Figures

Fig. 5. Caligus fistulariae Yamaguti, female. A. habitus, dorsal. B. caudal rami, dorsal. C. antennule. D. antenna, postantennal process, and maxillule. E. maxilla. F. maxilliped. G. sternal furca. H. leg 1. I. distal part of leg 1. Scales=A. 1 mm. B-H. 0.1 mm. I. 0.05 mm.