Is this frontonia oral opening, or some other opening?

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macnmotion
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Joined: Mon Sep 26, 2022 3:13 am

Is this frontonia oral opening, or some other opening?

#1 Post by macnmotion » Tue Feb 07, 2023 2:31 am

I believe I found my first frontonia. Here is an image with 10x objective.
is this frontonia sm.jpg
is this frontonia sm.jpg (62.63 KiB) Viewed 2192 times
I shot some video at 40x, here is a short clip. Is this the oral opening or something else?


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

Re: Is this frontonia oral opening, or some other opening?

#2 Post by Bruce Taylor » Tue Feb 07, 2023 4:22 am

It is not Frontonia, which has a very different kind of mouth, shaped like a peaked doorway, with an undulating membrane on one side, three rows of fused cilia on the other side, and preoral and postoral "sutures" at each end. Some other features of Frontonia we don't see here: a generally flattened cell; at least one contractile vacuole, usually near the middle; trichocysts around the outer margin.

It's hard to say what we have here! It could be a somewhat compressed Trachelius (it would normally have a short "proboscis"...however, that structure can disappear when the cell is squashed under a coverslip).

macnmotion
Posts: 524
Joined: Mon Sep 26, 2022 3:13 am

Re: Is this frontonia oral opening, or some other opening?

#3 Post by macnmotion » Tue Feb 07, 2023 4:49 am

Bruce Taylor wrote:
Tue Feb 07, 2023 4:22 am
It is not Frontonia, which has a very different kind of mouth, shaped like a peaked doorway, with an undulating membrane on one side, three rows of fused cilia on the other side, and preoral and postoral "sutures" at each end. Some other features of Frontonia we don't see here: a generally flattened cell; at least one contractile vacuole, usually near the middle; trichocysts around the outer margin.

It's hard to say what we have here! It could be a somewhat compressed Trachelius (it would normally have a short "proboscis"...however, that structure can disappear when the cell is squashed under a coverslip).
Thanks Bruce. There were a number of what seemed to be very small contractile vacuoles. In this very short video you can see them all over the place. I've slowed the video to about 3/4 speed.


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

Re: Is this frontonia oral opening, or some other opening?

#4 Post by Bruce Taylor » Tue Feb 07, 2023 1:05 pm

Hmmm...very hard to be sure what's going on, there! FWIW, Trachelius does have multiple contractile vacuoles, scattered around the cell (I am thinking of that genus mainly because of the overall appearance of the cytoplasm, and the round mouth). But, whatever this is, I think it is squashed beyond recognition. Definitely not Frontonia, in any case.

macnmotion
Posts: 524
Joined: Mon Sep 26, 2022 3:13 am

Re: Is this frontonia oral opening, or some other opening?

#5 Post by macnmotion » Wed Feb 08, 2023 4:44 pm

Bruce Taylor wrote:
Tue Feb 07, 2023 4:49 am
It's hard to say what we have here! It could be a somewhat compressed Trachelius (it would normally have a short "proboscis"...however, that structure can disappear when the cell is squashed under a coverslip).
Just to close the loop on this one, after about 20 slides I found another of these organisms in the same water sample, this time the proboscis was clearly visible. The excess debris won't make for a good video but at least I was able to find it. It surely looks like trachelius to me. It came in at about 320 microns in length including the proboscis.
trachelius with bars sm.jpg
trachelius with bars sm.jpg (61.82 KiB) Viewed 2087 times
Trachelius.jpg
Trachelius.jpg (91.44 KiB) Viewed 2087 times
Trachelius proboscis.jpg
Trachelius proboscis.jpg (104.1 KiB) Viewed 2079 times

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

Re: Is this frontonia oral opening, or some other opening?

#6 Post by Bruce Taylor » Wed Feb 08, 2023 7:27 pm

Ah, well there it is: Trachelius ovum. :) The cytoplasm is distinctive, as is that little round donut of a mouth.

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