Surface morphology of the fish parasite Chonopeltis victori Avenant- Oldewage, 1991 and aspects of the histomorphology

Abstract

The ultrastructure and aspects of the histomorphology of Chonopeltis victori, parasitic on Labeo rosae, L. congoro, L. ruddi, L. cylindricus and Barbus marequensis, are described from scanning electron micrographs and transverse sections. Chonopeltis victori is characterised by sharply pointed tips of the abdomen which are directed outward. Sexual dimorphism is particularly evident from the structure of the natatory lobes on the fourth swimming legs and the accessory copulatory structures on the second, third and fourth swimming legs of males. The most striking feature on leg four of the male is the peg. The elevated peg appears tubular, but the sides are not fused. On the inner collar elliptical projections, each with a central, circular pore, are present. On the elongated outer collar small indentions occur peripherally. The dorsal surface of the peg is subterminally covered by elongated scales. The ventral surface of the thorax and swimming legs are covered with different shapes of posteriorly directed scales. Interspersed amongst these scales, as well as on the dorsal surface, eight types of setae are present in large numbers. The possible function of the peg and other structures are described.