An ultrastructural investigation of Argulus personatus Cunnington, 1913 (Crustacea: Branchiura) from Lake Tanganyika, northern Zambia

Sixteen male and one female specimen of Argulus personatus Cunnington, 1913, were collected from Bathybates ferox Boulenger, 1898, from Lake Tanganyika in northern Zambia. Light and scanning electron microscopy (SEM) examinations documented a thickening of cuticle located on the dorsal surface between last thoracic segment and abdomen, which was rectangular in shape; a basal section of the pre-oral spine and proboscis ornamented with simple scales; three large simple setae present on the distal end of the basal plate; the dorsal distal end of second podomeres of maxillae ornamented with scales resembling those of a fish; second and third podomeres of maxillae ornamented with two types of pectinate scales (with fine bristle-like ends and scales with large pointed ends); the ventral distal end of third and fourth maxillary podomeres bearing large teardrop-shaped scales; a pair of tubular structures present adjacent to the anterior projection; a peg on the fourth pairs of legs of males bearing shallow grooves running irregularly across surface; and an accessory cushion bearing minute projections. These characters differed from the original description of A. personatus and are addressed in a redescription.