Life in cold blood: Exploring the cryptic diversity of species of Haemogregarina in Southern Africa's terrapins.

Species of Haemogregarina (Apicomplexa: Haemogregarinidae) are among the most common and widely distributed obligate apicomplexan blood parasites of primarily aquatic ectothermic vertebrates. Several species of Haemogregarina have been described infecting terrapin species globally, only two of which, Haemogregarina maputensis and Haemogregarina pelusiensi, have been described from Pelusios sinuatus, in Southern Africa. Several initial descriptions of species of Haemogregarina, including H. maputensis and H. pelusiensi, were based on the morphological analysis of erythrocytic parasite life stages. As species of Haemogregarina display high morphological similarity in the peripheral blood gamont stages, the integration of morphological and molecular techniques is essential in the study of these parasites today. Herein, the diversity of Haemogregarina species in freshwater terrapin hosts from Southern Africa is assessed using morphological and molecular techniques. Three genotypes were identified, two of which conform morphologically to H. maputensis and H. pelusiensi, warranting the supplemental description and molecular characterisation of these species. The third appears to represent a cryptic sister species of H. pelusiensi, exhibiting some variation in early developmental stages, warranting the description of a new species, Haemogregarina afrolatens n. sp.