Haptophyte

Haptophytes are a phylum of algae, sometimes called the Prymnesiophyta. All or most of them are single-celled photosynthetic phytoplankton.
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. 
Classification.
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.