• Actinocyclus undulatus : Bailey
• Actinocyclus senarius : Ehrenberg (1838)

 Solitary, more rarely in colonies of 2 or 3 cells. In valve view the cells have a discoid shape, while in girdle view they appear rectangular. The valves are divided into 6 sectors of equal size, raised sectors alternating with depressed sectors. In every sector, a rimoportula, a small external tube, can be seen by optical microscope. The hexagonal central area is smooth. The cell contains numerous large chloroplasts

Marine.

Distribution: as Actinoptychus senarius: Atlantic Ocean: Canary Islands (Gil-Rodríguez et al., 2003); North America: Nova Scotia (Kim, Garbary and McLachlan, 2004); Antarctic: Antarctic (Scott and Thomas, 2005).
As Actinoptychus undulatus: Europe: Spain (Varela, 1982).

Phytoplankton dynamics in Pomquet Harbour, Nova Scotia: a lagoon in the southern Gulf of St., Lawrence. Phycologia 43, Kim K.Y., Garbary D.J., McLachlan J.L., 2004, 311-328.

Diatoms. In: Antarctic marine protists. (Scott, F.J. & Marchant, H.J. Eds), Canberra & Hobart: Australian Biological Resources Study; Australian Antarctic Division, Scott F.J., Thomas D.P., 2005, 13-201.

Verbreitung und einfluss des mikroskopischen lebens in Süd- und Nord-Amerika., Akad. Wiss. Berlin, Ehrenberg C.G., 1843, 291-466, Pls 1-4

Proctoctista. In: Lista de especies marinas de Canarias (algas, hongos, plantas y animales). (Moro, L., Martín, J.L., Garrido, M.J. & Izquierdo, I. Eds), Las Palmas: Consejería de Política Territorial y Medio Ambiente del Gobierno de Canarias., Gil-Rodríguez M.C., Haroun R., Ojeda Rodríguez A., Berecibar Zugasti E., Domínguez Santana P., Herrera Morán B., 2003, 5 - 30

Catálogo florístico de las diatomeas bentónicas de las costas de Galicia, Collectanea Botanica 13(2), Varela M., 1982, 987 - 996