Fig. 3

Morphological features of gametocytes, which are used for identification of Haemoproteus species parasitizing Accipitriformes birds. Microgametocytes (a–c) and macrogametocytes (d–f) of Haemoproteus janovyi (a–c), H. elani (d), H. buteonis (e) and H. nisi (f). Note the markedly variable form of H. janovyi gametocytes (a–c), the broadly halteridial form of H. elani gametocyte (d), the presence of unfilled spaces on the poles of infected erythrocytes during H. buteonis infection (e), and the circumnuclear form of H. nisi gametocyte, which is overfilled with volutin granules (f). Images a–c are from the type material, which is fading, resulting in pale staining and poorly recognizable pigment granules and nuclei, however the overall form of the gametocytes is readily visible. Long simple arrows—host cell nuclei. Short simple arrows—parasite nuclei. Simple arrowheads—pigment granules. Simple wide long arrows—unfilled space on poles of infected erythrocytes. Triangle wide arrowheads—volutin granules. Other explanations are given in the text