Achromatorida

Achromatorida
Scientific classification
Domain: Eukaryota
Kingdom: Chromalveolata
Superphylum: Alveolata
Phylum: Apicomplexa
Class: Aconoidasida
Subclass: Haemosporidiasina
Order: Achromatorida
Suborders and Families
  • Babesiina
  • Theileriina

Achromatorida is an order of non-pigmented intraerythrocytic parasitic protozoa belonging to the subclass Haemosporidiasina. The order was created by Jacques Euz茅by in 1988.[1]

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.

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Description

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.

Taxonomy

It has two suborders:

Notes

There are also a number of genera of uncertain placement that have been provisionally included in this taxon:

Elleipsisoma Franca 1912

The family Dactylosomatidae (genera Babesiosoma Jakowski and Nigrelli 1956 and Dactylosoma Labb茅 1894) and the genus Anthemosoma Landau, Boulard and Houin 1969 were transferred to the suborder Eimeriorina by Boulard et al in 1982.

The genus Nicollia Franca 1910 is now regarded as a synonym for Babesia.[2]

Synonoms

The classification of the species in this group is difficult. Over the passage of time several genera have been described only to re classified as being synonoms of previously described genera.

Recognised synonoms of the genus Babesia include:

Recognised synonoms of the genus Nicollia - which is now itself regarded as a synonym of Babesia - include:

Recognised synonoms of the genus Theileria include:

Notes

Apiosoma is currently the name of a genus of ciliated protozoa also known as Glossatella. Although this genus is pathogenic to fish it has not related to the parasites in this taxon.

Nuttallia Dall 1898 is a genus of sunset clams (Psammobiidae)

References

  1. ^ Euz茅by, J. (1988) Comparative Medical Protozoology, Vol. 3: Apicomplexa, 2: Haemosporidioses, Part 1: Plasmodiids, Haemoproteids, "Piroplasms" (general characters)
  2. ^ Levine ND (1984) Nomenclatural corrections and new taxa in the apicomplexan protozoa. Trans Am Micro Soc 103 (2) 195-204