Coccolithophyceae
Class
Coccolithophyceae only includes calcified forms that possess organic body scales. Taxa within this class have a haptonema, which can be coiled and typically have two equal flagella.
Class Prymnesiophyceae retains non-calcified forms, which may or may not have organic body scales. Like Coccolithophyceae, taxa within this class can also have a coiled haptonema and two equal flagella.
Class Pavlovophyceae includes non-calcified forms that do not have organic body scales. This class is characterised by having two unequal flagella and a short, uncoiled haptonema.
These distinctions help identify and classify various species based on their calcification, organic body scales and specific morphological features of their flagella and haptonema.
Casper, S.J. von 1972. Observations on the fine structure of the flagellar apparatus in Chrysomonads. I. Uroglena americana Calkins. Archiv für Protistenkunde, 114: 65–82.
Hibberd, D.J. 1976. The ultrastructure and taxonomy of the Chrysophyceae and Prymnesiophyceae (Haptophyceae): a survey with some new observations on the ultrastructure of the Chrysophyceae. Journal of the Linnean Society of London, Botany 72: 55–80.
Rothmaler, W. 1951. Die Abteilungen und Klassen der Pflanzen. Feddes Repertorium Specierum Novarum Regni Vegetabilis. 54: 256-266.
