Actinophrys

Actinophrys is a genus of heliozoa, amoeboid unicellular organisms with many axopodial filaments that radiate out of their cell. It contains one of the most common heliozoan species, Actinophrys sol. It is classified within the monotypic family Actinophryidae.

Characteristics
Actinophrys species belong to an informal group known as heliozoa, which are unicellular eukaryotes (or protists) that are heterotrophic (also known as protozoa) and present stiff radiating arms known as axopodia. In particular, Actinophrys species are characterized by axonemes consisting of double interlocking spirals of microtubules. Their axonemes end on a large central nucleus. They are also characterized by the siliceous material present in their cysts.

Systematics
Actinophrys was described in 1830 by German naturalist Christian Gottfried Ehrenberg, with the type species Actinophrys sol. The species originally belonged to a genus named Trichoda, described earlier by Otto Friedrich Müller and later declared obsolete. In 1824, Bory de St. Vincent transferred that species to a new genus Peritricha but, without any new observations to justify the change, it fell out of use.

Species
There are currently four accepted species of Actinophrys.


 * Actinophrys sol (=A. difformis ; A. marina ; A. stella ; A. oculata ; A. tenuipes ; A. fissipes ; A. longipes ; A. tunicata ; A. limbata ; A. paradoxa ; A. picta ; A. alveolata ; A. subalpina ; A. vesiculata )
 * Actinophrys pontica
 * Actinophrys salsuginosa
 * Actinophrys tauryanini