A hollow marine
unicellular organism, between 20 and 150 µm across, hollow with a hard organic outer cell wall. This is
resistant to geological decay, so they survive as
microfossils, and are classified as
palynomorphs, that is fossil structures studied in
palynology along with other hard microscopic parts such as the outer walls of
pollen. Their exact genetic affinity is unknown. They might be some form of
alga. Visually, they have numerous spikes on the outer surface.