Bean-Shaped Ciliates – help ID?

Jul 29, 2016 • 10:27 AM UTC

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Microorganisms

MaxCoyle

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I have always found a lot of humour in observing the behavior of macroscopic animals. I can’t say why certain things are funny – the way a cat yawns, or a penguin waddles – but I like the simplicity and concreteness of this humor, the lack of punchline.
One unexpected delight of observing the Microcosmos under Foldscope is that I find the same humor in the behaviors of single-celled organisms. The physical comedy of Vorticella continually bumping into another ciliate in one of my previous posts is a good example: https://microcosmos.foldscope.com/?p=17546
Here, I will show the behavior of a ciliate (I think?) that I discovered recently. If you know what this is, please let me know in the comments!
This creature is rather large compared to other ciliates I have seen, and is shaped like a kidney-bean (or maybe just a kidney…) It moves in a couple of ways: a rotation around a fixed point, and a predatory-like circling. It seems to be quite a hungry bean, as it’s transparent insides appear full of algae or other food.

I was lucky to observe multiple of these ciliates interact, exchanging a quick greeting, reminding me of Manu’s post about the “handshakes” of single-celled organisms: https://microcosmos.foldscope.com/?p=17382
Also, at the end of the clip you will see me squishing the slide, causing the ciliates to expel (or other verb) their contents. Rather than explode, all the intracellular stuff seemed to come out of the same orifice, making me wonder if this is indeed a ciliate, or perhaps a small metazoa with a rudimentary digestive tract? It is unclear if the creatures keep living when I release the pressure on the slide. One appears to wriggle, but I didn’t image long enough to be certain.