[1][2] Heteronema trispira has a spindle-shaped body up to 130 μm long, twisted into a spiral with three characteristic counterclockwise turns.

It has a central nucleus, two long flagella and an apparently smooth periplast that tapers to a "snout-like" extension.

The cell is filled with very small paramylon grains.

[2] Observations have been recorded from wetlands in Ukraine,[1][4] Bulgaria[5] and Germany.

[2] One cell was recorded from a freshwater lake in Florida.