Actinoptychus senarius

Click on image to view photo information.
Taxonomic Group:Diatom
Trophic Status:Autotrophic
Size Range:40-85 μm diamter (Cupp 1943); 20-150 μm diameter (Tomas 1997; Horner 2002)
Key Characteristics:Cells round with numerous large chloroplasts; valves divided into sectors, usually six, which are alternately raised and depressed (alternate sectors not in same plane as others)
Confused With:At first glance could be mistaken for other pill box type diatoms such as Cyclotella or Thalassiosira but focusing up and down under transmitted light reveals the characteristic valve features mentioned above
Toxin:None known