Paramecium busaria, Frontonia, or other?

[Numanoid]

https://www.youtube.com/watch?v=2BthvqKZSc0

I found this in some lake water near my house. I googled and thought it was a Paramecium busaria, but another viewer suggested it was a Frontonia. What do you think? How did you come to that conclusion (in other words, what should I be looking for to positively identify it in the future?)

I'm very new to this so I don't have knowledge to even search for what they could be. Every day I learn quite a bit though by viewing others' finds.

Thanks!

[Bruce Taylor]

It is neither Paramecium nor Frontonia. At a few points--most clearly, at 0:32--we see an oral structure called the "cytopharyngeal basket" on the side of the cell, in the anterior (a structure of rigid microtubules, useful for eating cyanobacteria). That puts your ciliate in the order Nassulida. It is also uniformly covered with extrusomes (trichocysts). These are not distributed at odd angles (as in Nassula ornata), but very closely spaced and perpendicular to the outer membranes of the cell. To me, that suggests it is in the family Furgasoniidae (Furgasonia or Parafurgasonia). The overall appearance of the ciliary rows (nicely revealed at 0:33) is also consistent with Furgasonia. Do you know the size of the creature?

[KD Arvidsson]

Very nice and sharp film! //KD

[Bruce Taylor]

Because of the cell's shape (rather Frontonia-like!), I think it is likely to be Furgasonia blochmanni, described in 1967 as Cyclogramma blochmanni: https://onlinelibrary.wiley.com/doi/pdf ... PsAxkgC1KQ

[DonSchaeffer]

great pictures. I see these all the time. I figured they were some kind of paramecium, but really didn't know.

[Bruce Taylor]

Further to the above, here's a labelled still from your video, showing the cytopharyngeal basket:

Furgasonia.JPG (17.63 KiB) Viewed 2967 times

And here's a pic from an article on Furgasonia blochmanni (note the trichocysts, all around the outside of the cell, and the centrally-located contractile vacuole):

Furgasonia blochmanni.JPG (59.9 KiB) Viewed 2967 times

(From Part I of Eisler, 1988: https://www.sciencedirect.com/science/a ... 3988800129 )

By the way, the algae in the cytoplasm of your organism are food, not symbionts (as in Paramecium bursaria). Algal endosymbionts are perfectly uniform in size and colour, while ingested algae will show gradations from bright green to brown, depending on phase of digestion. Often, the size of ingested particles varies, too.

[Numanoid]

Thank you all for the information and kind words on the video. I learned a lot reading through it. As I read through Bruce's reply I googled the various terms and looked for them in my video. It was quite cool seeing cytopharyngeal basket after you mentioned it. I thought it was some kind of focusing or texture artifact. It's a good reminder to vary focus of a subject while observing it.

I'm bummed that the algae isn't chlorella, but now I have a new goal to find some endosymbionts. Your tip that ingested algae varies in color is also helpful.

Looks like I'm going to have to change my video title.

Thanks again!

[Bruce Taylor]

It was quite cool seeing cytopharyngeal basket after you mentioned it. I thought it was some kind of focusing or texture artifact. It's a good reminder to vary focus of a subject while observing it.

Taxonomy makes hidden things visible.