Ultrastructure of Lamproglena pulchella (Copepoda: Lernaeidae), a gill parasite on the freshwater fish, Leuciscus vorax, from Tigris River, Iraq

A new record of Lamproglenine copepods, Lamproglena pulchella were
collected from the gills of cyprinid freshwater fish Leuciscus vorax from the Tigris
River, Iraq in order to investigate the morphological and functional characteristics of
their appendages using scanning electron microscope. A maxilliped appears robust,
and bears at its apex two subequal curving, claw-like spines. First legs were with a
small protuberance on medial margin of the sympod near the base; endopod
apparently unsegmented, exopod indistinctly two-segmented, with several setae on
lateral margin and single stout seta on apex. Second legs have two segmented rami;
endopod unarmed and exopod with single seta on lateral margin of basal segment
and three setae at apex. Third and fourth pairs of appendages were similar, with alike
rami and with only two setae at the apex of exopod. These appendages are thought to
serve as a holdfast for attachment on the gill filament of the tigris fish. Cuticular
differentiations found on the body surface of L. pulchella play a secondary role in
the attachment of the copepod on its host. Current study microscopy shows that the
maxillae of L. pulchella are characteristically prehensile and thus provides an
efficient tool for the attachment to the host tissue.