Caligus lutjani, Ho & Lin & Chang, 2007

Ho, Ju-Shey, Lin, Ching-Long & Chang, Wen-Been, 2007, Four species of Caligus Müller, 1785 (Copepoda, Siphonostomatoida, Caligidae) parasitic on marine fishes of Taiwan, Journal of Natural History 41 (5 - 8), pp. 401-417 : 413-416

publication ID	https://doi.org/ 10.1080/00222930701203853
persistent identifier	https://treatment.plazi.org/id/0393EE77-FFAE-FFB1-FDC4-D63634957588
treatment provided by	Carolina
scientific name	Caligus lutjani
status	sp. nov.

Treatment

Caligus lutjani n. sp.

( Figures 8–10 View Figure 8 View Figure 9 View Figure 10 )

Material examined

Two ♀♀ on gills of two-spot red snapper, Lutjanus bohar (Forsskål) , collected on 21 July 2004 at Mi-tuo Fishing Harbor in Kaohsiung County, and 3♀♀ and 2 „„ in gill cavity of mangrove red snapper, Lutjanus argentimaculatus (Forsskål) , collected on 10 November 2004 off Ken-Ding in PingDong County. Holotype female ( USNM 1086713 View Materials ), allotype male ( USNM 1086714 View Materials ), and two female paratypes ( USNM 1086715 View Materials ) have been deposited in the US National Museum of Natural History , Smithsonian Institution , Washington, DC and the remaining paratypes and other specimens kept in the author’s ( CLL) collection.

Female

Body ( Figure 8A View Figure 8 ) 5.15 (4.68–5.62) long, excluding setae on caudal ramus. Cephalothoracic shield subcircular, 2.12 (2.00–2.24)X2.20 (2.04–2.36), excluding lateral hyaline membrane. Fourth pediger distinctly wider than long, 0.32 (0.28–0.36) X0.61 (0.56–0.66). Genital complex bottle-shaped, 1.65 (1.50–1.80)X1.33 (1.32–1.34), with slightly protruded posterolateral corners. Abdomen appearing two-segmented, proximal segment 0.57 (0.50–0.64)X0.46 (0.42– 0.50) and anal segment 0.46 (0.36–0.56)X0.44 (0.40–0.48); anal segment ornamented on ventral surface with setule-bearing papillae and patch of denticles as shown in Figure 8H View Figure 8 . Caudal ramus ( Figure 8H View Figure 8 ) longer than wide, 162 (146–178)X1.06 (97–113) mm. Egg sac not seen.

Antennule ( Figure 8B View Figure 8 ) two-segmented; both proximal and distal segments armed as in C. arii ; distal segment long, about 3.73 times as long as wide. Antenna ( Figure 8C View Figure 8 ) threesegmented; proximal segment smallest, armed with bluntly pointed process on posteromedial corner; middle segment subrectangular and bearing small adhesion pad on ventral surface; distal segment a claw strongly bent at tip and carrying two setae in basal region. Postantennal process ( Figure 8C View Figure 8 ) a small, bent claw bearing two papillae in basal region, each tipped with four setules, another similar setule-bearing papilla nearby on cephalon. Mandible ( Figure 8D View Figure 8 ) as in C. arii . Maxillule ( Figure 8C View Figure 8 ) comprising short, bluntly pointed digitiform process and papilla bearing three unequal setae. Maxilla ( Figure 8E View Figure 8 ) generally constructed as in C. arii , except subterminal hyaline membrane on brachium (distal segment) becoming a spiniform process. Maxilliped ( Figure 8F View Figure 8 ) three-segmented and constructed as in C. arii , except having a simple (instead of pinnate), distal seta on shaft. Box of sternal furca ( Figure 8G View Figure 8 ) oblong, carrying two diverging tines with sharp tips.

Armature of rami on legs 1–4 as in C. dactylus . Leg 1 ( Figure 9A View Figure 9 ) protopod with plumose, outer seta and another plumose, inner seta in addition to a setule-bearing papilla on outer margin and a patch of spinules on ventral surface; vestigial endopod small, tipped with two setules; first segment of exopod with row of setules on posterior edge; middle two of terminal four elements with accessory process connected to spine proper by hyaline membrane. Leg 2 ( Figure 9B View Figure 9 ) constructed essentially as that in C. dactylus . Leg 3 ( Figure 9C View Figure 9 ) protopod (apron) with short, outer and long, inner, plumose seta; large marginal membrane on outer edge following serrated margin and another marginal membrane on posterior edge of basis inner to velum; setule-bearing papilla on basis near both ends of this posterior membrane. Leg 4 ( Figure 9D View Figure 9 ) protopod produced subterminally on outer margin before insertion of plumose, outer seta; exopod twosegmented; proximal segment with setule-bearing papilla on outer margin; short, bipectinate, spiniform process on both exopodal segments at insertion of each five outer spines. Leg 5 (inserted drawing in Figure 8A View Figure 8 ) represented by two papillae on posterolateral margin of genital complex, with one bearing one small, plumose setae and another with two similar setae.

Male

Body ( Figure 10A View Figure 10 ) 4.86 (4.74–4.98) long, excluding setae on caudal rami. Cephalothoracic shield subcircular, 2.21 (2.12–2.30)X2.17 (2.08–2.26), excluding lateral marginal membranes. Fourth pediger distinctly wider than long, 0.28 (0.28–0.28)X0.58 (0.56– 0.60). Genital complex long, 1.22 (1.20–1.24)X0.68 (0.66–0.70), bearing setule-bearing papillae on ventral surface and lateral margin ( Figure 10D View Figure 10 ). Abdomen two-segmented, proximal segment longer than wide, 0.56 (0.56–0.56)X0.37 (0.36–0.38), but anal segment subsquare, 0.45 (0.42–0.48)X0.42 (0.40–0.44). Caudal ramus longer than wide, 215 (211–219)X146 (138–154) mm.

Antenna ( Figure 10B View Figure 10 ) three-segmented; proximal segment unarmed; middle segment largest, with two unequal corrugated pads on medial surface; terminal segment produced into a small plate with short, sharp claw and two basal setae. Corpus of maxilliped ( Figure 10C View Figure 10 ) robust, with three (two sharp and one blunt) processes in myxal area; in closing, tip of claw inserting into trough in largest, middle process. Leg 5 ( Figure 10D View Figure 10 ) constructed as in female. Leg 6 not seen.

Etymology

The new species is named after its host—the fishes of the genus Lujanus.

Remarks

Caligus lutjani is characterized by a combination of the following four features: (1) the twosegmented abdomen is about one-half the length of the genital complex; (2) sternal furca has a pair of diverged, sharply pointed tines; (3) middle two of the terminal four elements on the exopod of leg 1 are armed with accessory process; and (4) leg 4 has a formula of I-0; I,III. This combination of morphological features is shared with only one of more than 250 congeners— Caligus noυocaledonicus Kabata, 1968. However, close comparison with the latter showed that the specimens from Taiwan belong to a different species. The differences found in C. lutjanus are: (1) the lack of a conical projection at the base of the postantennal process; (2) presence of a bipectinate, spiniform process on the exopod of leg 4 near the insertion of each of the five outer spines (see Figure 9D View Figure 9 ); and (3) a long (versus broad) caudal ramus. The host of C. noυocaledonicus is Lethrinus miniatus Forster View in CoL , caught in New Caledonia. The parasite has not been reported again since the publication of its original description by Kabata (1968).