Tachysoma pellionellum

[janvangastel]

I found it very difficult to ID this ciliate and I may be wrong of course.
The easiest part of ID-ing this ciliate was finding out that it is a hypotrich. But there are many hypotrichs. The one I observed is a slender one, which has al least two macro nucleii. Maybe four, because it looks like the two are divided into two each. The contracting vacuole is about mid body and the ciliate has two relatively straight rows of cirri on his body. Length of the creature is about 85 microns. There are also ciri at the front and at the end. It is rounded at the rear end. As far as I understand, there are no caudal cirri. This altogether I arrived at Tachysoma pellionellum.

[Bruce Taylor]

A very nice, clear video showing the distribution of cirri clearly! I think you're right that it's Tachysoma pellionellum. All of your observations are consistent with that species, and the trailing transverse cirri are distinctive. We don't see dorsal cilia, but these might be below the focal field.

There are just two macronuclear nodules. The dividing line you see is a "replication band," a visible feature that appears on the spirotrich macronucleus during DNA replication (the S phase of cell division).

[janvangastel]

Thanks Bruce. Nice that I have it right.

[75RR]

Do like to watch your videos, always something interesting to see.

Very impressed by your methodical approach to identifying your specimens ... you seem to be a scientist at heart!

[janvangastel]

Thank you 75RR. I learn this approach mostly from Bruce's comments on my video. And yes, I am (was, I am retired) a scientist, but in a very different domain: psychology.