Hello,
2 weeks ago, I sampled a small sapropelic puddle on a street and found hundreds of these small (~80 ยต) nassulids (with a lot of other interesting ciliates).
There are 2 conspicuous features:
- Arranged "bumps" on the pellicle.
- A V-shaped slit in front of the cyrtos (Cyclogramma?)
Couldn't find an ID, perhaps you could :)