Characterization of Henneguya kadeyensis sp. nov. (Myxosporea: Myxobolidae) infecting Distichodus mossambicus from Kadey River, Cameroon.

African freshwaters are inhabited by many endemic fishes. However, little is known about the associated myxozoan diversity. The present paper describes a new parasite species of Henneguya Thélohan, 1892 infecting Distichodus mossambicus Peters, 1852, an endemic freshwater fish species commonly found in the Congo Basin. Fish were collected from the Kadey River at Mindourou, a village in the East Region of Cameroon. To study the new Henneguya species, morphological analysis using light microscopy was combined with a phylogenetic analysis of small subunit ribosomal DNA (SSU rDNA) using maximum likelihood and Bayesian inference methods. White and elongated plasmodia were found in the gill lamellae. The myxospore body was 11.5 ± 0.2 (mean ± SD) (range: 10.4-12.7) µm long, 3.3 ± 0.1 (2.7-3.9) µm wide, and 2.3 ± 0.1 (1.9-2.9) µm thick. The caudal appendages were 22.1 ± 0.4 (20.1-25.9) µm long and the total length of the new species was 29.7 ± 0.3 (27.5-32.3) µm. The 2 pyriform polar capsules were of the same size, 3.7 ± 0.1 (3.2-4.2) µm long and 1.0 ± 0.03 (0.9-1.2) µm wide. Phylogeny of the SSU rDNA showed the new Henneguya species within a subclade composed exclusively of unidentified Myxobolidae infecting African Citharinoidei fish. Further work characterizing myxozoan species using both morphological, molecular, and phylogenetic data is required to better understand myxozoan diversity in Africa.