Synonym: Prymnesiophyceae Hibberd 1976
Full reference: W. Rothmaler. 1951. Die Abteilungen und Klassen der Pflanzen. Feddes Repertorium Specierum Novarum Regni Vegetabilis 54:256-266
Parent taxon: Haptophyta according to M. A. Ruggiero et al. 2015
See also Silva et al. 2007 and Young and Bown 1997
Sister taxa: Aspidorhabdus, Camuralithus, Conococcolithus, Corannulus, Craspedolithus, Crassapontosphaera, Crassidiscus, Cricosphaera, Cyclolithella, Cycloperfolithus, Discoasteridae, Duplexipodorhabdus, Ellipsodiscoaster, Helicosphaera, Heliorthus, Koczyia, Leptodiscus, Lithostromationaceae, Nannocorbis, Orthozygus, Pervilithus, Phanulithus, Pyrocyclus, Reticulofenestra, Rhabdolithina, Sphenaster, Striatococcolithus, Syracosphaera, Umbilicosphaera, Vermiculithina, Wiseorhabdus
Subtaxa: Arkhangelskiales Athenagalea Biantholithus Braarudosphaerales Calyptrosphaeraceae Ceratolithaceae Coccolithales Coccosphaerales Cyclicargolithus Daktylethra Discoasterales Discoasteroides Eiffellithales Ellipsagelosphaeraceae Ellipsolithus Eodiscoaster Gladiolithus Goniolithaceae Ilselithina Isochrysidales Lanternithus Lapideacassaceae Minylitha Neosphaera Pedinocyclus Phaeocystales Podorhabdales Prymnesiales Prymnesiophycidae Rhomboasteraceae Sphenolithus Stephanolithiales Syracosphaerales Tetralithoides Tetralithus Transversopontis Watznaueriales Zygodiscales
Ecology: passively mobile planktonic "photoautotroph"