Taxonomy of the coccidia is based upon morphological descriptions of observed parasites, and therefore does not always reflect evolutionary relationships.[3] Genetic studies of the well-conserved SSU rRNA from various specimens has suggested that parasites in Cyclospora may be more closely related to some species of Eimeria that infect birds than the rest of the genus Eimeria is.[3][4] Relationships among various coccidia estimated for SSU rRNA sequences are shown in the cladogram below:[4]
^ abcSlapeta J, Morin-Adeline V (2011). "Coccidia, Leuckart 1897". Tree of Life Web Project. Retrieved 18 July 2018.
^ abMorrison DA, Bornstein S, Thebo P, Wernery U, Kinne J, Mattsson JG (2004). "The current status of the small subunit rRNA phylogeny of the coccidia (Sporozoa)". International Journal for Parasitology. 34 (4): 501–514. doi:10.1016/j.ijpara.2003.11.006. PMID15013740.
^Curry A, Smith HV (1998). "Emerging pathogens: Isospora, Cyclospora, and microsporidia". Parasitology. 117: S143 –S159. doi:10.1017/S0031182099004904.
