Bean-Shaped Ciliates – help ID?


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:

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:

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.

All for now…hope everyone has a nice weekend!


5 Comments Add yours

  1. Manu Prakash says:

    What an incredible find @Max. I am absolutely astounded. I have a few points to make. But my money would be on – “nyctotherus” which is new to the Foldscope community.

    1) Your first intuition that the motility is driven by cilia is correct; since looking closely I can see cilia beating and some fluid flow right on the surface. Many “flatworms” are also ciliated – so your alternative hypothesis of a metazoan is also credible.

    2) But quickly looking at my “ciliate identification guide” I posted a couple of weeks ago – link here:

    Skimming quickly, number 24 – “nyctotherus” comes to mind. So right now; that’s what I will stick with. I find the dense granules and one very large vacuole as a good matching criteria.

    3. On your point about bursting – ciliates have incredible capacity to heal (see latest paper by Wallace marshal lab – – love the “double decker” configuration. It’s normal when you get one hole in the membrane; to have all the cytoplasm flow out from the same orifice. So it is consistent with being a single cell organism.

    I would love to know how/where you got this sample? Watch some more.. next time we meet; I can show you how to do a little bit of phase contrast to improve resolution.

    Great find.


  2. MaxCoyle says:

    @Manu, nyctotherus seems like a good candidate! And exciting to have possibly added a new organism to the ever-expanding Foldscope catalogue.

    The wound healing study is very interesting – has me thinking about different ways to perturb Foldscope samples for studying behavior.

    This sample was actually from the Sleeping Protozoa kit from Sciento. It’s been a fascinating culture, very lively, diverse, and dynamic over time.

  3. Matthew Rossi says:

    I agree that one of the joys of looking at the microcosmos is the humor of the creatures there. I adore the views I get of ciliates darting about, or the worried, fraught twirl of a bacterium circling its way across the field of view. The nycotherus seems like an earnest sort of microbe. It doesn’t seem to need to move unless it has something to do. You can’t say the same of a paramecium, for example. These are great videos.

  4. laksiyer says:

    @Max. I am seeing this or a relative now and I think it is Colpoda. I wonder if this too is Colpoda.

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