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I've become more and more fascinated by Ciliates, especially since I can grab them out of a larger sample using a stereo scope and transfer them to a flat slide. Here are three that I observed in the last few days in case anyone might find them interesting.

I had some help from Bruce in identification. The first is Nassulopsis, the second is Paramecium Brusaria and the third is likely Amphileptus or Litonotus. All came from an algae sample from a local pond. Objectives were all Olympus Splan Apos, either 10x,20x or 40x.

https://vimeo.com/365034973

Great detail, Nicely done!

Excellent.

Bruce generally knows more about ciliate taxonomy than I do, but that seems peculiar for Nassulopsis. The figures I have seen are typically relatively slender, with multiple contractile vacuoles along the side, which even though this is a good video are not evident to me here. What keeps this from being some other type of Nassophorea? (Assuming Nassulopsis themselves still belong to that class; they may not.)

Hi Josh, those are very good points. My thinking here was that the blue spot is pretty distinctive, so this was likely to be a compressed specimen, similar to this one posted by Michael Plewka (of Plingfactory fame):
(from https://www.mikroskopie-forum.de/index.php?topic=6021.0 ) He is a careful observer, but certainly not infallible (I've found a few oddities on his site!), so his specimen might not be a useful data point regarding morphological variation in the genus.

The specimen shown by Foissner et al in the 4-vol "Atlas" also has a broad appearance, though more pyriform (and with a better view of the multiple CVs):
However, it may also be that there's a different nasse/cyrtos-bearing ciliate with a blue pigment spot that I'm not aware of...or one that hasn't been documented at all! Another oddity of this one, is the relatively large size of the oral "basket." To be sure of where this belongs in the ciliate tree we'd really need to see whether it has a "hypostomial frange" in what Deroux calls "the Nassulopsis pattern" (completely encircling the cell). I didn't see the frange at all (or any kind of preoral suture) when I watched the video last night, but will look at it again to see if I missed it. (ETA: just watched again, and I can see the outside edge of the frange--that little tuft that appears from time to time on the margin of the cell near the mouth. But the camera doesn't focus on that structure at any point, so we're unable to see how far it goes).

Alas, Nassulopsis is not in class Nassophorea, presently, but in Phyllopharyngea, subclass Cyrtophoria, order Synhymeniida (along with Zosterodasys and Chilodontopsis). So, if we're being very scrupulous about identification, and we happen to suspect this fellow might be a blue-spotted nassulid (e.g. Nassula or Obertrumia), then we couldn't go any lower than subphylum Intramacronucleata...which, of course, contains most ciliate species, apart from the heterotrichs and karyorelicteans!

I didn't do a search on blue-spotted nassulids, incidentally...could be I'm just not aware of one that would fit this critter perfectly! If not, it could also be a new, undescribed extra-chubby species of Nassulopsis. So far, the genus only has the one species, I think, but there may be some unnoticed diversity within it (whether "sp.", "subsp." or "var"!)

BTW, the first critter is probably Amphileptus procerus, a fairly common species.

...and an interesting writeup on Nassulopsis by the talented Martin Kreutz (a colour update from one of his old Mikrokosmos articles): https://mikro-tuemplerforum.at/viewtopic.php?t=438

Speaking of morphological variation...here's a fatso with three cytopharyngeal "baskets"!

Just for the record, my understanding is that Synhymeniida were moved out of Nassophorea based on RNA trees like in Gong et al., 2009. But they note that Nassulopsis are different from the others in having polykinetids, and Sola et al. thought they actually belong with the Nassulida. Lynn left them with Synhymeniida pending molecular data, which so far as I know is still pending; a couple years ago Dr. Song had kindly answered me about their placement and considered it unresolved.

At least Foissner, 1979 mentions a second species, N. paucivacuolata, where the contractile vacuoles were much smaller but the cell still very narrow in shape. As ciliates that show up in puddles, it would be no surprise if others have been missed. I know I've never noticed the blue spot in the ones I have seen, but that could as easily be a failure of observation.

Thank you Heather and 75RR.

And thank you Bruce and actinophrys for your help and illustrious discussion !!

Great videos as usual mintakax. Very interesting discussion too!

actinophrys wrote: ↑

Tue Oct 08, 2019 10:04 pm

Just for the record, my understanding is that Synhymeniida were moved out of Nassophorea based on RNA trees like in Gong et al., 2009. But they note that Nassulopsis are different from the others in having polykinetids, and Sola et al. thought they actually belong with the Nassulida. Lynn left them with Synhymeniida pending molecular data, which so far as I know is still pending; a couple years ago Dr. Song had kindly answered me about their placement and considered it unresolved.

At least Foissner, 1979 mentions a second species, N. paucivacuolata, where the contractile vacuoles were much smaller but the cell still very narrow in shape. As ciliates that show up in puddles, it would be no surprise if others have been missed. I know I've never noticed the blue spot in the ones I have seen, but that could as easily be a failure of observation.

I think your summary of the taxonomy is right on the money. I remember now that we talked about Nassulopsis a couple of years ago (and I still haven't run across one in my own samples!). I'm sure it will land in the nassulids, in the end...it just looks and acts like one.

Looking at the Sola article again, I see he also proposed the blue spot as a "unique generic character" for Nassulopsis, so it does seem to be a pretty distinctive feature.

I also looked more closely at the recap of the taxonomy in Foissner et al., 1994, and was surprised to see that at least half a dozen species are recognized (with the number of CVs varying from 1 to 20). More variation there than I knew!

And after all that...I just watched the mintakax's excellent video again, and now think I'd completely misread the nature of the blue matter. I don't think it's a pigment spot, after all! As I should have noticed before, the stuff is circulating in the cell, and some of it has even collected in the posterior. We see that fairly clearly in the later clips.

So, I now think these are just the usual coloured digestive products of an ordinary Nassula, and I was misled by the fact that they're mostly blue, and (in the early part of the video) concentrated in the anterior of the cell. I think actinophrys was right all along!

Wes wrote: ↑

Wed Oct 09, 2019 7:02 am

Great videos as usual mintakax. Very interesting discussion too!

Thanks Wes !