Is this a Hypotrich?

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Jerradin
Posts: 54
Joined: Thu Jul 30, 2020 9:48 pm

Is this a Hypotrich?

#1 Post by Jerradin » Wed Sep 09, 2020 3:36 pm

I'm a novice at this, so I'm just looking to confirm some of my IDs. I believe, based on what I can see, that this is some kind of Hypotrich. Is that correct?

Here's a video recording: https://www.youtube.com/watch?v=unJGIB4MV-g

Here's an image with a scale bar. It's blurry, but useful for size.
Image
Here are the important things I'm seeing:
1. AZM
2. One contractile vacuole that opens and closes
3. About 250 micrometers long
4. Flexible body (hard to tell in this recording, but before I started recording it was really squishing itself around in the substrate)
5. Caudal cirri (again, not too obvious in the recording, but they popped out when I closed the condenser)
6. I may be fooling myself, but I think I can just barely make out kineties in lines running along the length of the body, especially in the light area under the AZM. Am I crazy?

If I am correct that this is a Hypotrich, is there any reasonable way for me to narrow the ID down further? It seems like going beyond that requires the ability to count groupings of cilia, and I certainly don't have the equipment for that.

Bruce Taylor
Posts: 986
Joined: Fri Sep 04, 2015 11:34 am

Re: Is this a Hypotrich?

#2 Post by Bruce Taylor » Wed Sep 09, 2020 5:41 pm

Nice big ciliate. :) Yes, it's a hypotrich (i.e. it's in subclass Hypotrichia...it's customary to use lower case for the adjectival form, upper for formal name). Without seeing somatic ciliation and undulating membranes there is no way to put it in a lower taxon. It could be an oxytrichid (e.g. Cyrtohymena). On the other hand, it could be a urostyloid (e.g. Urostyla). If you really did see caudal cirri (and not trailing transverse cirri, or long posterior marginals), that would rule out certain genera, but it wouldn't be enough to get the ID down to an order or family. We do see some ventral cirri below the AZM, but not enough to narrow down the ID. The overall appearance and diet make me suspect a urostyloid, but we can't be sure.

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