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
The most notable group is the silicoflagellates, marine plankton that form siliceous skeletons and are well known as fossils.
Most other axodines form a group variously called the pedinellids or actinodines.
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.
- Cavalier-Smith T., Chao E. E., Allsopp M. T. E. P. (1995) Ribosomal RNA evidence for chloroplast loss within Heterokonta: pedinellid relationships and a revised classification of ochristan algae. Arch. Protistenkd. 145: 209-220.
- Mikrjukov K.A., Patterson D.J. (2001) Taxonomy and Phylogeny of Heliozoa. III. Actinophryids. Acta Protozoologica 40: 3-25
- Sandgren, C.D.; Smol, J.P.; Kristiansen, J. (1995). Chrysophyte Algae: Ecology, Phylogeny and Development. Cambridge University Press. p. 49. ISBN 9780521462600. Retrieved 2014-12-12.