Ochromonadales

Ochromonadales is an order of single-celled algae belonging to the class Chrysophyceae, also known as golden algae. Initially it contained numerous groups of flagellates that were not closely related. During the late 20th century, advancements in molecular and ultrastructural studies allowed the transfer of many of these groups out of Ochromonadales, and the order was reduced to a single family Ochromonadaceae. They are aquatic single-celled flagellated algae, with two heterokont flagella each, some of which have secondarily lost their chloroplasts and appear colorless.

== Description == Species of this order are flagellates, composed of cells capable of swimming by using two flagella. Though ancestrally photosynthetic, some species have secondarily lost this ability, and appear colourless. These are heterotrophic, and can be phagotrophic. Some are mixotrophic, capable of both photosynthesis and phagotrophy, such as Poterioomonas and Ochromonas. They can be found in marine and freshwater habitats. == Systematics == === Taxonomic history === Ochromonadales is an order of golden algae (class Chrysophyceae), a group of photosynthetic heterokonts (phylum Ochrophyta). It initially contained numerous families united only by being primarily monadoid (flagellate), palmelloid or amoeboid throughout their life cycle. For this reason, it included completely unrelated organisms such as the Bicosoecaceae (now outside the phylum Ochrophyta) or the Pedinellaceae (now in class Dictyochophyceae).