Acanthocephala of cichlids (pisces) in Lake Malawi, Africa, with a description of Acanthogyrus (Acanthosentis) malawiensis sp. n. (Quadrigyridae) from Labeo cylindricus peters, 1852 (Cyprinidae)

Two species of acanthocephalans are reported from fishes collected during the summer of 1996 in the southeast arm of Lake Malawi (Lake Nyasa), East Africa. The common Acanthogyrus (Acanthosentis) tilapiae (Baylis, 1948) had infected 18 cichlid and 1 bagrid host species (all new host records) netted by divers wearing scuba gear around Harbor Island or caught by hook and line in deep water. The specimens of this parasite were some of the smallest ever reported for that species. Two males of a new species, Acanthogyrus (Acanthosentis) malawiensis, are described from 2 male Labeo cylindricus (Cyprinidae). This is the fifth species of this genus and subgenus described in Africa. It is distinguished from the other 4 African and 33 mostly Asian species in that the proboscis hooks of the middle circle are longer than those of the anterior circle. The new species further differs from the other African species in proboscis and hook size, posterior hook root, trunk spination, and lemniscal form. Observations on host and geographical distribution, prevalence, and developmental stages of A. (A.) tilapiae are also reported.