Phylogenetic assessment of <i>Plasmodium</i> (<i>Saurocytozoon</i>) <i>tupinambi</i> comb. nov. (Haemosporida, Plasmodiidae) in golden tegu lizards: shedding light on a long-standing Haemosporida taxonomic puzzle

Haemosporidians constitute a monophyletic group of vector-borne parasites that infect a wide range of vertebrate hosts, including Neotropical lizards. The remarkable diversity of these host-parasite associations and inadequate research on certain parasite groups have resulted in controversial haemosporidian taxonomy. Herein, we rediscover erythrocytic and non-erythrocytic haemosporidians infecting golden tegus (<i>Tupinambis teguixin</i>) from Brazil and Colombia. The erythrocyte-inhabiting parasite belongs to <i>Plasmodium</i> sp., and the non-erythrocytic form was identified as <i>Saurocytozoon tupinambi</i>, previously attributed to the Family Leucocytozoidae. These non-pigmented haemosporidian parasites do not multiply in the blood. The relationships between the <i>Saurocytozoon</i> and Leucocytozoidae species were discussed for many years, especially during the 1970s. However, cytochrome b (<i>cytb</i>) sequences and the mitochondrial genomes recovered for this species strongly support classifying this parasite as a <i>Plasmodium</i> taxon. Therefore, we proposed a new combination for this parasite, <i>Plasmodium</i> (<i>Saurocytozoon</i>) <i>tupinambi</i> comb. nov., where <i>Saurocytozoon</i> is retained as a subgenus due to its distinct morphology. These results reinforce that a broader definition of Plasmodiidae must include saurian parasites that develop non-pigmented leucocytozoid-like gametocytes.