Astrolithus Tertiory group(discoasters) have been eandtinguished in Pliocene age. Although Bursa reported live remnants similar to discoasters in North Pole, in 1965, lout this manner has been proved so for and discovering of Boursa can be resulted from contamination of sediments. Despites an organism is not observed from discounters but most of investigators believe that disco asters have been remained in side of cell likely after calcification and they have not been desecrated around it.
Discoaster has different and compile morphology but they have a simpler structure rather than coccolithus. Discoasters do not convert hexagonal and rhombohedra crystals to calcite but they turn them to vitrite. Their radial tentacle has been made of vitrite crystals.