Caligus dakari

Boxshall, Geoff A & El-Rashidy, Hoda H., 2009, A review of the Caligus productus species group, with the description of a new species, new synonymies and supplementary descriptions, Zootaxa 2271, pp. 1-26 : 10-12

Caligus dakari van Beneden, 1892

Syn: Caligus mauritanicus typical form Brian 1924

Differential diagnosis: Female genital complex and abdomen combined about 1.5 times longer than cephalothorax; body length 6.0– 6.5 mm. Male body length 5.0 mm. Female genital complex ( Fig. 3 A) elongate with parallel lateral margins and narrow waist-like region anteriorly, lacking distinct postero-lateral lobes: abdomen 2-segmented, first segment nearly three times longer than second. Male abdomen 2- segmented ( Fig. 4 A); second segment longer than first. Post-antennal process large and strongly curved in both sexes (cf. Figs 3 B, pap; 4B, pap). Additional process present between post-antennal process and base of antenna in female ( Fig. 3 B). Posterior process of maxillule ( Fig. 4 B, mxl) with distinct narrowing between proximal and sital parts; male with tiny blunt accessory process. Sternal furca with strongly incurved tines and wide gape; transverse thickenings of body surface present either side of furca ( Fig. 4 D). Female maxilliped with smooth medial margin. Male maxilliped with pointed process on myxal margin ( Fig. 4 C), opposing tip of claw; process minutely concave at tip. Exopod of leg 1 with seta at inner distal angle shorter than segment and about as long as terminal spine on distal margin; posterior margin with single plumose seta less than half length of adjacent seta ( Fig. 4 E). Exopod of leg 4 distinctive in both sexes ( Fig. 3 C, 4F): first exopodal segment large with marginal setules, second segment with concave margin proximal to first marginal spine: exopodal spines relatively stout, outer 2 spines of similar length and markedly shorter than terminal spine.

Material examined: 30 female and 3 male syntypes labeled Caligus mauritanicus , in 2 vials deposited in the collections of the Museum National d’Histoire Naturelle in Paris, registration numbers, MNHN Cp.278 and Cp.280.

Distribution: Eastern South Atlantic: Mauritania, Senegal.

Hosts: Carangidae : Lichia amia (Linnaeus, 1758) ;

Sciaenidae : Argyrosomus regius (Asso, 1801) (as Sciaena aquila ).

Remarks: The original description of C. dakari was incomplete and inadequate by modern standards and even though Brian (1924) recognised a remarkable similarity in gross form between C. mauritanicus and C. dakari , he preferred to establish a new species. Van Beneden’s (1892) description specified that the plumose setae were absent on the posterior margin of the distal exopodal segment of leg 1 of C. dakari , which allows us to place it in the productus -group. In addition, this is an unusually large species of Caligus . These two nominal species are the only species currently known from the Atlantic coast of Africa that lack these setae, share this shape of genital complex and elongate abdomen, and have a female body length of about 6.0 mm. We consider these species to be identical. The oldest available name for this species is C. dakari and we here recognise the typical form of Caligus mauritanicus Brian, 1924 as a junior subjective synonym.

Kirtisinghe (1964) considered that the specimens of Caligus arii Bassett-Smith, 1898 reported from South Africa by Barnard (1955) belonged to C. dakari .

Figures

FIGURE 3. Caligus dakari van Beneden, 1892 female. A. genital complex and abdomen, ventral view; B. antenna, postantennal process (pap) and maxillule (mxl), ventral view in situ; C. leg 4. Scale-bars: A = 1 mm, B = 200 μm, C = 250 μm.

FIGURE 4. Caligus dakari van Beneden, 1892 male. A. genital complex and abdomen, ventral view; B. antenna, postantennal process (pap) and maxillule (mxl) in situ, ventral view; C. maxilliped; D. sternal furca in situ; E. second exopodal segment of leg 1 showing distal armature; F. leg 4. Scale-bars: A = 500 μm, B, C, D, F = 250 μm, E = 100 μm.