| Coscinodiscus, Asteromphalus, Diploneis, Thalassiosira weissflogii, Thalassionema nitzschioides|
Actinocyclus is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Actinocyclidae. In 2006, a study was carried out which included finding traces of extinct Actinocylidae in Russia, which ultimately assisted geologists in dating its prevalence and significance to history. Out of 7236 samples found, they concluded that this species belongs to a group of known as Actinocyclus gorbunovii. Freshwater species of Actinocyclus were also found to have a major part in playing a stratigraphic marker, also known as an estimated time in which geologists can use to help order things in a sequence of events. Using K-Ar dating, scientists concluded that Actinocyclus species were found to be most optimal in the middle-age Miocene era.
This genus is not to be confused with Actinocyclus Ehrenberg, 1837 , a genus of diatoms in the family Hemidiscaceae.
Species in the genus Actinocyclus include:Actinocyclus papillatus (Bergh, 1878)
Actinocyclus verrucosus Ehrenberg, 1831