Caligus alaihi Lewis, 1968

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 : 8

Caligus alaihi Lewis, 1968

Differential diagnosis: Female genital complex and abdomen combined shorter than cephalothorax; body length 2.77 mm. Male body length 2.07 mm. Female genital complex lacking distinct postero-lateral lobes; abdomen apparently 1-segmented, about half as long as genital complex. Male abdomen 2-segmented; second segment almost twice length of first. Post-antennal process sexually dimorphic, larger and more strongly curved in male. Sternal furca with straight, strongly divergent tines. Female maxilliped with smooth medial margin. Male maxilliped with slight rounded swelling in myxal area. Exopod of leg 1 with seta at inner distal angle about as long as segment, single plumose seta on posterior margin about as long as shortest distal spine. Outer margin of second endopodal segment of leg 2 ornamented with denticles. Leg 4 ornamented with marginal setules on protopodal segment but none figured on exopodal segments: outer spine on second exopodal segment reaching well beyond base of adjacent distal margin spine; terminal spine about twice as long as other 2 distal margin spines.

Material examined: none

Distribution: Eniwetok Atoll.

Hosts: Holocentridae : Neoniphon samara (Forsskål, 1775) (as Holocentrus samara ).

Remarks: This species can be readily distinguished within the group by the short, 1-segmented abdomen of the adult female. It differs from C. enormis in which the abdomen is even more reduced and fused to genital complex and which lacks a sternal furca. It carries a single, well developed plumose seta on the posterior margin of the distal exopodal segment of leg 1 as in C. pagrosomi . In C. enormis this seta is present but is spinulate, rather than plumose, and one of the distal margin spines is lacking ( Ho & Bashirullah 1977).