Anuretes quadrilaterus Shiino, 1954

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 : 209-211

Anuretes quadrilaterus Shiino, 1954

( Figs. 24-26 ) Anuretes quadrilaterus Shiino, 1954, p. 264 , figs. 3-5;

Ho and Lin, 2003b, p. 300, figs. 1, 2; Ho and Lin, 2004,

p. 98, figs. 49, 50.

Material examined. 1¥, 1J from the gill chambers of Zenopsis nebulosa (Temminck and Schlegel) , at Yangpo Port, Pohang-shi, Gyeongsangbuk-do, I.-H. Kim, 21 November 2009 .

Female. Body ( Fig. 24A ) 5.65 mm long. Cephalothoracic shield nearly circular, 3.75× 3.85 mm; ventral rib of lateral zone L-shaped, abruptly bent distally; posterior margin of thoracic zone concave; posterolateral pit absent. Fourth pedigerous somite short and concealed by thoracic zone of cephalothoracic shield. Genital complex 1.86× 2.17 mm, wider than long, with rounded corners. Abdomen small, wider than long ( Fig. 24B ), fused with genital complex, 298 µm wide, 1-segmented, its proximal one-third slightly wider than distal two-thirds. Caudal rami ( Fig. 24B ) remotely separated from each other and divergent; each ramus 158×115 µm, distinctly broadened distally, with 6 setae.

Antennule 2-segmented; proximal segment with 27 setae (25 pinnate and 2 naked); distal segment elongated, much longer than proximal segment, with 12 naked setae and 2 aesthetascs. Antenna 3-segmented; first segment with small proximal process ( Fig. 24C ); second segment nearly quadrangular; third segment forming large, robust claw bearing 2 small setae. Postantennal process short, with 2 papillae tipped with setules; another papilla locat- ed posterior to postantennal process tipped with 4 setules.

Mandible with 12 teeth distally. Maxillule consisting of anterior papilla bearing 3 small setae and posterior process bearing strongly tapering distal tine ( Fig. 24C ). Maxilla ( Fig. 24D ) slender and 2-segmented; proximal segment (lacertus) unarmed, with parallel lateral margins; distal segment (brachium) gradually narrowed distally, with rudimentary flabellum in middle of inner margin; calamus 354 µm long and canna 150 µm long. Maxilliped ( Fig. 24E ) 3-segmented; first segment (corpus) stout, with 1 weak process on inner margin; second segment (shaft) short, with 1 distal seta; third segment almost fused with second, forming stout claw. Sternal furca ( Fig. 24F ) with blunt, slightly divergent distal tines bearing hyaline flange on inner margin.

Armature on rami of legs 1-4 as follows:

Leg 1: exopod 1-0; III,1,3; endopod 3

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

Leg 3: exopod I-1; III,I,5; endopod 0-0; 6 (or 5)

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

Leg 1 ( Fig. 24G ) basis with pinnate outer and inner setae. Proximal exopodal segment with 1 small outer distal naked seta and row of setules on distal part of inner margin; distal segment widened distally; two inner distal spines bifurcating at their midlength; distal seta small, not longer than distal spines ( Fig. 24H ); endopod small and tipped by 3 setae (or processes). Leg 2 ( Fig. 25A ) coxa with large seta on inner posterior margin and 1 minute setule on ventral surface; basis with small outer seta. Leg 3 ( Fig. 25B ) with 2-segmented rami; distal endopodal segment with 5 or 6 setae. Leg 4 ( Fig. 25C ) protopod slightly expanded at proximal third; distal exopodal segment much longer and slender than proximal segment. Leg 5 represented by 1 small setae on lateral margin of genital complex and small plate bearing 3 small setae on posterolateral margin of genital complex ( Fig. 24A ).

Male. Body ( Fig. 26A ) with large cephalothoracic shield and small urosome, 2.94 mm long. Cephalic shield resembling that of female. Genital complex strongly tapering ( Fig. 26B ), 0.79× 1.09 mm. Abdomen small, much wider than long and 1-segmented. Caudal ramus 89×90 µm.

Antennule ( Fig. 26C ) armed as in female, but distal segment relatively longer than that of female. Antenna ( Fig. 26D ) 3-segmented as in female; first segment unarmed; second segment with several weakly developed adhesion pads; third segment with 2 inner proximal setae and short bifurcate distal claw. Postantennal process as in female.

Mandible and maxilla as in female. Maxillule ( Fig. 26E ) with narrow distal tine bearing corrugation and 1 small seta. Maxilliped ( Fig. 26F ) with more prominent process on inner margin of first segment. Sternal furca with narrower and distinctly divergent tines.

Legs 1-4 as in female. Leg 5 similar to that of female ( Fig. 26G ). Leg 6 represented by 3 posterior setae on genital complex ( Fig. 26G ).

Distribution and host. Only from Zenopsis nebulosa (Temminck and Schlegel) in Japan ( Shiino, 1954), Taiwan ( Ho and Lin, 2003b), and Korea (present study).

Remarks. This is the third record of occurrence for A. quadrilaterus Shiino, 1954 , following the original ( Shiino, 1954) and Ho and Lin’s (2003b) records. From both Japan and Taiwan, the host was Zenopsis nebulosa and hence this species is considered as host-specific to Z. nebulosa . Shiino (1954) observed only five setae on the lateral margin of the male genital complex, a difference from our observation that the margin carries seven setae consisting of the anterior 1+3 setae as leg 5 and the posterior 3 setae as leg 6.

Figures

Fig. 24. Anuretes quadrilaterus Shiino, female. A. habitus, dorsal. B. abdomen, ventral. C. antenna, postantennal process, and maxillule. D. maxilla. E. maxilliped. F. sternal furca. G. leg 1. H. distal part of leg 1. Scales=A. 1 mm. B, D, F-H. 0.1 mm. C, E. 0.2 mm.

Fig. 25. Anuretes quadrilaterus Shiino, female. A. leg 2. B. leg 3. C. leg 4. Scales=A. 0.2 mm. B, C. 0.1 mm.

Fig. 26. Anuretes quadrilaterus Shiino, male. A. habitus, dorsal. B. urosome, dorsal. C. antennule. D. antenna. E. maxillule. F. maxilliped. G. legs 5 and 6. Scales=A. 0.5 mm. B. 0.2 mm. C-G. 0.1 mm.