Polystoma galamensis (Monogenea): Occurrence and ecological range in Nigeria

Abstract

Hylarana galamensis collected from three biotopes in Nigeria were investigated for infection with the monogenean Polystoma galamensis. Of the 152 specimens examined, 19 (12.5%) were infected with the parasite. Prevalence in the guinea savannah was 21.4%, derived savannah, 15.1% and the freshwater creeks of Ase, 2.27%. The intensity of infection was generally low and this can be principally attributed to the solitary reproductive behaviour of the host. Excessive precipitation and flooding may additionally play limiting roles in the creeks of the Niger Delta. Irrespective of host habitat, parasites recovered from frogs in Nigeria showed close similarity with the type species from Togo in several aspects of their morphometrics. The parasite from Nigeria also had a low haptor/body ratio and the occurrence of prehaptoral intestinal anastomoses was infrequent. This close similarity between the parasites from Togo and Nigeria confirms P. galamensis as a valid species. This report from Nigeria is the second on the parasite, making Nigeria a new geographical record for the parasite.

Keywords: Hylarana galamensis; derived savannah; freshwater swamp; guinea savannah; Polystoma galamensis; Nigeria