These setae are mainly used for attachment to the host, each other,and protection from potential pathogens. The second charicteristic are the valves or body portions. These can take a variety of shapes and arrangements, and have been used to aid in the taxonomy of this species. The final charicteristic is the colony formation. Very rarely do Chaetoceros cells live alone.
Cells can be straight or twisted along the axis.
These are divided mainly into two subgenera, Phaeoceros and Hyalochaete. Those organisms within the taxa Phaeoceros are typically larger than Hyalochaete's with large,wickedly barbed setae. Most HAB Chaetoceros are within this taxa, including Ch. Click on each of these taxa to learn more about them.