Ciliate or a worm?

[Free2Fish]

Does anyone have any idea what this could be. I think it’s a ciliate but can’t even be sure of that. Check out the strange appendage visible behind the head.

https://youtu.be/BkHkcj870js?si=DSXo4EGyg75JFoNp

Cheers, Harry

[zzffnn]

Nice video, Harry.

That look like a ciliate. I don’t know what that appendage is; I am guessing it may be an injury. Bruce Taylor would be the expert to ask; or your can ask David Seamer on Facebook.

Was that video recorded using DIC (what scope brand and model)? What magnification? 20x?

[Free2Fish]

Thanks, zzffnn. I am leaning towards ciliate also, perhaps the genus Spirostomum. Your injury suggestion might be accurate since the little fellow endured a 4000 rpm centrifuge ride.
Yes, the video was shot with a Nikon Eclipse 400 adapted for DIC. I’m almost certain it was filmed at 40X, making the length a roughly estimated 150 microns.

Harry

[zzffnn]

Sometimes even gravity alone is enough to concentrate some ciliates. I would suggest maybe 200 rpm. In biology labs, we do no more than 800 rpm for eukaryotic cells.

[Free2Fish]

Thanks for the tip, I’ll give that a try. Several YouTube videos mentioned using 3 to 4 thousand rpm and most of the microbes seem OK with that but it does feel excessive.
I’ve only had the centrifuge for a couple of days but it’s given me way more to look over from the pond jars I set up last fall.

Harry

[Bruce Taylor]

Yes, it's a ciliate, but it's not Spirostomum, or any heterotrich. It is in class Litostomatea, subclass Haptoria. but unfortunately it is bent over, so we don't have a very clear view of its overall shape. We see a flattened cell with large posterior vesicle. An oral bulge is visible at several points, but we can't tell how long it is. Distribution of extrusomes is unknown. So, it could be a spathidiid (e.g. Bryophyllum, Spathidium, etc.), or a pleurostomatid (e.g. Loxophyllum). If you have more footage of the critter I'd be happy to have a look.

[Free2Fish]

Thanks so much Bruce, loads of reading to do now. Sorry, no other footage, had one but lost it again. I know what jar it came from so ill keep looking.