Caligus ariicolus Wilson, 1928

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 : 9

Caligus ariicolus Wilson, 1928

Differential diagnosis: Female genital complex and abdomen combined about 1.5 times longer than cephalothorax; body length 3.75–4.25 mm. Male length 3.0 mm. Female genital complex large, lacking distinct postero-lateral lobes; only slightly longer than abdomen; abdomen 2-segmented, first segment about 3 times longer than second. Male genital complex slender: abdomen 2-segmented; second segment longer than first. Post-antennal process sexually dimorphic, larger and more strongly curved in male. Sternal furca with incurved tines but narrow gape. Female maxilliped with smooth medial margin. Male maxilliped with process on myxal margin, opposing tip of claw. Exopod of leg 1 with seta at inner distal angle longer than longest distal spine but shorter than segment; no setae on posterior margin. First exopodal segment of leg 4 with large outer spine reaching nearly to tip of outer spine on second segment; outer spine on second exopodal segment long, about equal in length to outer and middle spines on distal margin; terminal spine distinctly longer than other 2 distal margin spines.

Material examined: none

Distribution: Thailand.

Hosts: Ariidae : Nemapteryx caelata (Valenciennes, 1840) (as Arius caelatus ).

Remarks: This species has a large genital complex and abdomen and is similar in body proportions to Caligus fugu Yamaguti & Yamasu, 1959 . However, it differs in the absence of the spinous process on the medial margin of the maxilliped of the female. The sternal furca of C. ariicolus has incurved tines whereas those of C. fugu are straight and tapering. Caligus ariicolous Wilson, 1928 was described from a catfish caught off Paknam, Thailand, and has not been reported since.