Actinocyclus octonarius   Ehrenberg,  1838 ()
Organism information awaits expert curation
Class: Bacillariophyceae

Image copyrights: Mona Hoppenrath

Cells are drum shaped with a flat valve face and a pronounced mantle that curves abruptly. Cells are usually solitary. Numerous chloroplasts are found around the cell margin and a cytoplasmic bridge may be seen. The cingulum consists of 2, possibly 3, bands. The valvocopula is wide but commonly destroyed during valve cleaning. The second band is much narrower than the valvocopula and has a pronounced ligula that fits into the opening of the valvocopula. Valves are circular in outline. The central annulus is highly variable (hyaline to completely areolate valve centers have been observed in clonal cultures). The areolae on the valve face are arranged in sectors, separated from each other by complete radial rows of areolae. Towards the distal end of these rows a single opening of the labiate process is visible. The density of areolation is considerably higher at the mantle than on the valve face.

Synonym (s)
Actinocyclus ehrenbergii Ralfs in Pritchard, 1861
Actinocyclus ehrenbergii Ralfs, 1861

Common Name (s)
Economic Importance and Threats

Habitat:  Estuarine


• Tamil Nadu, Off Tuticorin (Lat: 8.71) (Long: 78.2) INDIA (Record: 1987-1989)
• Bay of Bengal INDIA (Record: 06/07/2001-02/08/2001)
• Orissa, Rushikulya Estuary (Lat: 19.37) (Long: 85.05) INDIA (Record: 11/01/1989-12/01/1989)

Literature Source(s)
  • Subramanian, SK and Krishnamurthi, MS (1997) Studies on the species composition of neritic diatoms in the aquatic realm off Tuticorin Coast in the Gulf of Mannar-Bay of Bengal Seaweed Research and Utilisation Seaweed Research and Utilisation Association 19(1-2) 1-11 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Plankton*Net Data Provider at the Alfred Wegener Insitute for Polar and Marine Research Available at -
  • (2006) Algaebase Available at -
  • Paul, JT; Ramaiah, N; Gauns, M and Fernandes, V (2007) Preponderance of a few diatom species among the highly diverse microphytoplankton assemblages in the Bay of Bengal. Marine Biology springerlink 152(1) 63-75 Available at -
  • Gouda, R and Panigrahy, RC (1989) Diurnal variation of phytoplankton in Rushikulya estuary, east coast of India Indian Journal of Marine Sciences Scientific Publishers 18(4) 246-250 Available at - NIO, Goa

Page last updated on:2012-02-14

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