Is this Ophryoglena?

[NachoBen]

If so, any hint about the species?

Magnification x300.
https://youtu.be/8Zp7pmz8kTw

Magnification x1200.
Notice the pentagonal-hexagonal fields of the pellicle.
https://youtu.be/Hn16yge0xkI

Thank you very much!

[Dennis]

NachoBen,
Good stuff.

[Bruce Taylor]

Yes, it is almost certainly Ophyroglena. I didn't see the mouth (a very distinctive feature of the genus), but the overall appearance of the thing, and its slow, rotating movement, are typical. They are tissue-eaters (histophages), and this one has been feeding well. It is very plump, and full of food. The polygonal structures we see are not in the pellicle, but in the closely-packed, envacuolated contents of the cytoplasm (like soap bubbles, they can become somewhat polygonal when pressed together). I don't see any features that would help identify a species.

[NachoBen]

This is what I was afraid of. I knew that it would be impossible to determine this ciliate beyond gender but I had to try. Thanks again, Bruce, the information you provided about polygonal fields is very interesting.