Haemogregarines from western Palaearctic freshwater turtles (generaEmys, Mauremys) are conspecific withHaemogregarina stepanowiDanilewsky, 1885

Abstract

SUMMARYThe majority ofHaemogregarinaspecies have been based on the morphology of their erythrocytic stages and supposed strict host specificity. The quantity of species with a limited number of overlapping diagnostic traits has led to a considerable mess in haemogregarine taxonomy and significant synonymy. We analysed host specificity, intra- and interspecific variability, evolutionary relationships, and the distribution of the type species of the genusHaemogregarina–H. stepanowi.The morphology of blood stages and 18S rDNA sequences of this haemogregarine from four western Palaearctic hard-shelled freshwater turtles (Emys orbicularis, Mauremys caspica, Mauremys leprosaandMauremys rivulata) were compared withHaemogregarina balli. Additional sequences of 18S rDNA ofHaemogregarina-like isolates collected from three species of African hinged terrapins (genusPelusios) were used to enlarge the dataset for phylogenetic analyses. Thirteen sequences (1085 bp) ofHaemogregarinarepresenting all four western Palaearctic turtle species were identical, corresponding toH. stepanowi, which is closely related to the Nearctic speciesH. balli. In our analyses,Haemogregarinaspp. constituted a monophyletic clade sister to the genusHepatozoon. Haemogregarina stepanowipossesses a wide distribution range from the Maghreb, through Europe, Turkey and the Middle East to Iran. We consider that the genusHaemogregarinahas a low host specificity crossing the family level of its vertebrate hosts and that its distribution is likely to be linked to the vector and definitive host – the leech.