Distigma proteus (Ehrenberg, 1831)

Most likely ID: n.a.


Synonym: n.a.


Sampling location: Simmelried


Phylogenetic tree: Distigma proteus



  • body spindle-shaped, anterior end snout-shapaed
  • broadest part of body near anterior end
  • length 50–120 µm
  • two flagella of different length
  • numerous rod-shaped paramylon grains, mainly in anterior half
  • active euglenoid movement
  • nucleus central
  • distinct striation of the pellicle
Distigma proteus

So far I have only found Distigma proteus in the Simmelried. Especially in old samples with decomposing plant masses.


Members of the genus Distigma can be easily recognized by the two flagella of unequal length. This is the main difference to the genus Astasia. Within the genus Distigma, Distigma proteus is the largest representative, reaching a body length of over 100 µm. This prevents any confusion with comparable species.


According to my observations, Distigma proteus is considerably less metabolic than representatives of the genus Astasia. The secondary flagellum is often bent backwards and moves less than the main flagellum. The distinct striation of the pellicle runs counterclockwise. The anterior half of the cell was filled with ellipsoidal paramylon grains of about the same size with a length of about 5–7 µm. During swimming, the posterior end was often stretched out like a rod.


More images and information on Distigma proteus: Michael Plewka-Freshwater life-Distigma proteus


Fig. 1 a-f: Distigma proteus. L = 116 µm (of elongated specimen). A freely swimming specimen. Note the two flagella (F1, F2) of different length. Nu = nucleus, PG = paramylon grains. Obj. 60 X.