ID these two foraging critters

[Bschnitzer]

Platyhelminthes?

These two guys are about 150μ long. Whiskers at the mouth.

Thanks in advance.

Bob

B0C5E0C4-88D1-4563-B12E-FF8B448258A4.jpeg (87.94 KiB) Viewed 685 times

[Bruce Taylor]

They are ciliates....probably hypotrichs. Do you have any brightfield images? Dark field often does not show the features needed for ciliate identification.

[Bschnitzer]

Alas, no bright field on this one, Bruce. I only noticed longitudinal body striations and short sub anterior cilia scooping up food. Moved like a flatworm. They never rested, so it was difficult to get a sharp photograph.

[Bschnitzer]

I am processing a bright field video and will post later. This superb Charles Krebs image is the best match I can find. Certainly Hypotrich. Thanks again, Bruce.

9E1C6DDA-3CA2-456C-B40C-A9F536E0259C.jpeg (198.82 KiB) Viewed 645 times

[Bschnitzer]

Here is a bright field image at 100x and cropped to about 200x:

8EAA9B10-5B67-4313-96F7-1C02E7ECE57B.jpeg (108.43 KiB) Viewed 636 times

Original higher resolution image:

https://drive.google.com/file/d/1H8ILMU ... sp=sharing

Here is the video:

https://drive.google.com/file/d/1xAi6rr ... sp=sharing

[Javier]

That is an Hypotrich for sure.

[Bruce Taylor]

Yes, a hypotrich. To identify it below subclass, we'd need to see the distribution of cirri on the ventral surface. It resembles Urostyla, but there are other possibilities.

[Bschnitzer]

Bruce,

Re: ventral cilia distribution, are you referring to the amphisiellid median cirral row and adoral zone of membranelle cilia only, or other cilia groupings along the ventral side? If I run across these guys again, I’ll pay more attention to that area, though I don’t think my setup will be up to the task, photo resolution-wise. Thanks again for the help.