Achromatorida is an order of non-pigmented intraerythrocytic parasitic alveolates belonging to the subclass Haemosporidiasina.
These are minute rounded or pyriform parasites found within erythrocytes, or other circulating or endothelial cells of vertebrates.
A Bayesian analysis based on the nuclear genes suggests a date of divergence between Babesia and Theileria of 56.48 million years ago ( 95% credible interval 28.17 million years ago–86.87 million years ago)[2] This order is divided into two suborders: These are agents of piroplasmosis sensu stricto.
Species in this family have rhoptries, a polar ring and subpellicular tubules in its apical complex.
[3] These are parasites of erythrocytes and diverse white blood cells with sexual reproduction by exoerythrocytic or by exo- and endoerythrocytic schizogony.
The families Dactylosomatidae (genera Babesiosoma Jakowski and Nigrelli 1956 and Dactylosoma Labbé 1894) were transferred to the suborder Adeleorina by Boulard et al in 1982.
The position of the Anthemosomatidae (genus Anthemosoma Landau, Boulard and Houin 1969) remains unclear.