Published online by Cambridge University Press: 06 April 2009
Progarnia archosauriae nov. gen., nov. sp. (Haemosporina: Garniidae) is described in the blood of the South American caiman, Caiman crocodilus crocodilus (Archosauria: Crocodilia). The parasite undergoes merogony and gametogony principally in leucocytes and thrombocytes, but also invades erythrocytes in which it produces no ‘malarial’ pigment. It thus shares features of Fallisia and Garnia which are, respectively, intra-leucocytic and intra-erythrocytic haemosporines of the family Garniidae in present-day lizards. This, and the antiquity of the order Crocodilia, suggests that it was from such a parasite that the existing reptilian and avian haemosporines evolved. An overall evolutionary pattern is suggested.