iNaturalist observation: https://www.inaturalist.org/observations/170600154
Observation of four specimens of _Cryptomonas_ from the same water sample, made within two days. I am not sure if they belong to the same species, but the cell size and general morphology look very similar. At the beginning you can notice some Bodo-like Flagellate. And at the end of the video, in addition to two Cryptomonas, Cinetochilum margaritaceum ciliate is present.
Phylum: Cryptophyta. _Cryptomonas_ Ehrenberg, 1831.
The genus _Cryptomonas,_ which belongs to the class Cryptophyceae, was established by Ehrenberg (1831). The algae are common in freshwater habitats and brackish water worldwide and often form blooms in greater depths of lakes. Cells can be easily recognized by two unequal biflagella, olive-brownish to olive-greenish in color, large ejectisomes lined in the furrow-gullet system, and a peculiar swaying swimming behavior due to the asymmetric shape, dorsally flattened and ventrally concave in lateral view.
It seems to me these cells have four pyrenoids, indicated with question marks. It makes them similar to _Cryptomonas tetrapyrenoidosa._ (Roman Romanov)
A water sample was taken from the shore of Srednerogatsky Pond. The air temperature was 14°C (57.2 °F). The sample was stored at room temperature and observed 6 days after collection.
Music: Jesse Gallagher – Thin Places