Plasmodia of a Henneguya species measuring 70-900 pm and exhibiting season-dependent stages of development were detected throughout a three-year study on gill myxosporosis of Lake Balaton pikeperch (Stizostedion lucioperca (L.)). Sixty-five out of 160 fish (41%) examined in the period of study were infected by the parasite. Infection was the most prevalent (48%) among pikeperch specimens exceeding 40 cm in length. The highest prevalence of infection (58%) was recorded in 1995-1996 while the lowest (30%) in 1996-1997. The youngest plasmodia appeared in April, and started to develop within the capillaries of the secondary lamellae of the gill filaments. The round or ellipsoidal plasmodia which continued their gradual growth in the subsequent months of the year achieved a size of 800-900 pm by the late autumn months, but remained in intralamellar location throughout the developmental cycle. Mature spores developed in the plasmodia by the end of winter. On the basis of their shape and size, the spores were identified as Henneguya creplini (Gurley, 1894). However, because of the uncertain taxonomy of species assigned to the genus Henneguya the taxonomic position of the parasite requires further study. The host reaction consisting of epithelial proliferation and granulation tissue formation starts around the infected secondary lamella only after the maturation of spores and the disruption of plasmodia.
The genus Triaenops has been considered monospecific in its a frican and Middle Eastern range (T. persicus), while three other species have been recognised as endemic to Madagascar (T. menamena, T. furculus, and T. auritus), and another to the western Seychelles (T. pauliani). We analysed representative samples of T. persicus from East Africa and the Middle East using both morphological and molecular genetics approaches and compared them with most of the available type material of species of this genus. Morphological comparisons revealed four distinct morphotypes in the set of examined specimens; one in Africa, the others in the Middle East. The Middle Eastern morphotypes differed mainly in size, while the allopatric African form showed differences in skull shape. Two of three Arabian morphotypes occur in sympatry. Cytochrome b gene-based molecular analysis revealed significant divergences (K2P distance 6.4–8.1% in complete cyt b sequence) among most of the morphotypes. Therefore, we propose a split of the current T. persicus rank into three species: T. afer in Africa, and T. persicus and T. parvus sp. nov. in the Middle east. The results of the molecular analysis also indicated relatively close proximity of the Malagasy T. menamena to Arabian T. persicus, suggesting a northern route of colonisation of Madagascar from populations from the Middle east or north-eastern Africa as a plausible alternative to presumed colonisation from east Africa. Due to a considerable genetic distance (21.6–26.2% in 731 bp sequence of cyt b) and substantial morphological differences from the continental forms of Triaenops as well as from Malagasy T. menamena, we propose generic status (Paratriaenops gen. nov.) for the group of Malagasy species, T. furculus, T. auritus, and T. pauliani. We separated the genera Triaenops and Paratriaenops gen. nov. from other hipposiderid bats into Triaenopini trib. nov. recognising their isolated position within the family Hipposideridae Lydekker, 1891.