Axodine

The axodines (Actinochrysophyceae, Actinochrysea or Dictyochophyceae sensu lato) are a group of unicellular heterokont algae, previously classified in the Chrysophyceae.

They include pedinellids, silicoflagellates, and Rhizochromulinales.

Characteristics

They characteristically have a single emergent flagellum, which lacks the root structure found in related groups, and is extended into a wing-like form supported by an internal rod. They also have tentacles or axopods supported by triads of microtubules, arising from the surface of the nucleus.

Classification and history

Order Dictyochales

The most notable group is the silicoflagellates, marine plankton that form siliceous skeletons and are well known as fossils.

Order Pedinellales

Most other axodines form a group variously called the pedinellids.

Order Rhizochromulinales

In addition to the silicoflagellates and actinodines, the marine amoeboid Rhizochromulina marina is included here based on the structure of its zoospores. It is considered closer to the latter group than the former.