|Coccolithophore (Coccolithus pelagicus)|
The cells typically have two slightly unequal flagella and a unique organelle called a haptonema. This is superficially similar to a flagellum, but differs in its arrangement of microtubules, and in its use. The name comes from the Greek hapsis = touch, and nema = thread.
Molecular and morphological evidence places them in five orders; coccolithophores make up the Isochrysidales and Coccolithales. Other groups include phytoplankton which produce the toxic algal blooms.
- R.A. Anderson. 2004. Biology and systematics of heterokont and haptophyte algae. American Journal of Botany 91: 1508-1522.