portrait

Description:

Astasia (a-stays-ee-a) is a colourless euglenid, probably having derived from a lineage with plastids. With one emergent flagellum (by which it can be distinguished from Distigma which is similar but has two emergent flagella. There is no mouth, although this cell is unusual in that it has inclusions - indicating that it has ingested sulphur bacteria and cyanobacteria. Flagellum with whiplash beat (loops are flicked along the length of the flagellum, and in swimming cells these tend to be directed towards the rear so that the cell swims forward following a spiral path. Phase contrast.