The Plasmodiid Parasites
In the first decade of the 20th century the first reptilian malarial parasites were recognized, joining those reported from humans and birds within the previous 20 years. Wenyon (1909a), during his tenure as traveling protozoologist for the Wellcome Research Laboratories, found Plasmodium agamae and P. mabuiae in agamid and scincid lizards of the Sudan. In the same year, and with priority to Wenyon’s discovery, two species, Plasmodium diploglossi and P. tropiduri, were described from Brazil in anguid and tropidurid lizards (Aragão and Neiva, 1909). The pace of species discovery and description rose slowly until the 1960s, with only 29 species and subspecies recognized by Garnham from reptiles in his classic Malarial Parasites and Other Haemosporidia, which appeared in 1966. At the end of that decade, the recognition of Plasmodium species and species of related genera began to rise in seemingly geometric progression, with 87 taxa known by 1989 (Telford, 1994), then slowed in the 1990s, with 101 species and subspecies of Plasmodium sensu stricto described or under description by 2007, as well as 37 other related species of plasmodiids: Garnia (10), Fallisia (10), Haemocystidium (14), Saurocytozoon (2), and Progarnia (1). To a considerable extent, this proliferation resulted from long-term residence in endemic areas by parasitologists interested in these organisms, in contrast to brief visits with the limited collections possible by traveling scientists or physicians, often with other primary interests.