Achromatorida
| Achromatorida | |
|---|---|
| Scientific classification | |
| Domain: | Eukaryota |
| (unranked): | SAR |
| (unranked): | Alveolata |
| Phylum: | Apicomplexa |
| Class: | Aconoidasida |
| Subclass: | Haemosporidiasina |
| Order: | Achromatorida |
| Suborders | |
Achromatorida is an order of non-pigmented intraerythrocytic parasitic alveolates belonging to the subclass Haemosporidiasina. The order was created by Jacques Euzéby in 1988.
The taxonomy of these organisms has been one of some controversy. Weylon in 1926 grouped many of these genera into the genus Babesia - given what is now known about these genera this was probably an error. Agreement on the organisation of these genera probably cannot be regarded as being settled.
These are minute rounded or pyriform parasites found within erythrocytes, or other circulating or endothelial cells of vertebrates. The parasites reproduce by merogony without oocysts or spores.
The apical complex has a polar ring and rhopteries. A conoid is lacking and most species lack the associated pellicular microtubules.
Flagellae are lacking. The trophozoite stage is separated from erythrocyte by single membrane (in the other groups there usually 2 or more). Vectors include ticks and leeches.
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)
This order is divided into two suborders:
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