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.[3][4] 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.[2]
Systematics
Actinophrys was described in 1830 by German naturalist Christian Gottfried Ehrenberg, with the type speciesActinophrys sol. The species originally belonged to a genus named Trichoda, described earlier by Otto Friedrich Müller and later declared obsolete.[1] 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.[2]
Species
There are currently four accepted species of Actinophrys.[2]
Actinophrys sol(Müller, 1773) Ehrenberg, 1830[1] (=A. difformisEhrenberg, 1830; A. marinaDujardin, 1841; A. stellaPerty, 1852; A. oculataStein, 1854; A. tenuipesClaparède & Lachmann, 1858; A. fissipesLachmann, 1859; A. longipesLachmann, 1859; A. tunicataLachmann, 1859; A. limbataLachmann, 1859; A. paradoxaCarter, 1864; A. pictaLeidy, 1879; A. alveolataSchewiakoff, 1893; A. subalpinaWest, 1901; A. vesiculataPenard, 1901)
^ abCavalier-Smith, Thomas; Scoble, Josephine Margaret (2013). "Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes". European Journal of Protistology. 49 (3): 328–353. doi:10.1016/j.ejop.2012.09.002. PMID23219323.
^Gast, R.J. (2017). "Centrohelida and Other Heliozoan-like Protists". In Archibald, J.; Simpson, A.; Slamovits, C.; Margulis, L.; Melkonian, M.; Chapman, D.; Corliss, J. (eds.). Handbook of the Protists. Cham, Switzerland: Springer International. pp. 1–17. doi:10.1007/978-3-319-32669-6_28-1. ISBN978-3-319-32669-6.
^Valkanov A (1940). "Die Heliozoen und Proteomyxen. Artbestand und sontige kritische Bemerkung". Archiv für Protistenkunde. 93: 225–254.