ID help, if you have the time

billporter1456 · Post by **billporter1456** » Fri Jun 20, 2014 5:52 pm

This doesn't look like Vorticella, so is it Zoothamnium, Carchesium, or something else?

https://www.youtube.com/watch?v=SUtMCUflLZw

rjlittlefield · Post by **rjlittlefield** » Fri Jun 20, 2014 7:09 pm

This is not really my area, but see http://www.photomacrography.net/forum/v ... 218#148218 for some info copied out of Jahn.

--Rik

billporter1456 · Post by **billporter1456** » Sat Jun 21, 2014 5:56 am

rjlittlefield wrote:This is not really my area, but see http://www.photomacrography.net/forum/v ... 218#148218 for some info copied out of Jahn.

--Rik

Thanks, Rik!

pwnell · Post by **pwnell** » Sat Jun 21, 2014 8:56 am

If the previous ID of my photographs were accurate I believe these to be Zoothamniums. See here.

billporter1456 · Post by **billporter1456** » Sat Jun 21, 2014 1:24 pm

pwnell wrote:If the previous ID of my photographs were accurate I believe these to be Zoothamniums. See here.

Hi Waldo, those were stunning images! In your photos, and other photos I have found in the Internet, the common stalks are fairly thick and the individual stalks are very short. In my video, I can see individual stalks that are rather long, like a Vorticella stalk, and they contract in a coil like Vorticella. Also, I think Zoothamnium, though found in fresh water, are more common in sea water. I have about talked myself out of Zoothamnium for an ID, but I much appreciate you input on the matter.

Bruce Taylor · Post by **Bruce Taylor** » Sun Jun 22, 2014 6:04 am

Nice video.

Usually, these guys are identified by the arrangement of the stalk and the myoneme (spasmoneme), the long fibre which gives the stalk its ability to contract. Vorticella and Pseudovorticella have non-branching stalks, so they contract individually, even when clustered together in a big group. In Carchesium, Pseudocarchesium and Zoothamnium, large numbers of zooids (the bell-shaped cells) can share a myoneme, so they will contract together. In Carchesium and Pseudocarchesium, that myoneme is discontinuous (that is, it does not run from side groups into the "main trunk" of the colony), so parts of the colony will contract independently. In Entziella and Myoschiston, it is partially continuous (stopping short of the main trunk), and in Zoothamnium it is continuous. In Carchesium, the contraction is spiral (as in Vorticella), while in Pseudocarchesium it is "zigzag," like an accordion. (For more, see Curds et al, British and Other Freshwater Ciliated Protozoa, 196 ff.)

To be sure of the identification, here, we'd need to have a good close look at the stalks, to determine whether the myonemes are continuous or not. Does the main trunk contract along with the side groups? It's hard to tell, in this case. Also, we'd want to have clearer footage of the contractions, to confirm that they are spiral (as I suspect) and not "zigzag."

billporter1456 · Post by **billporter1456** » Mon Jun 23, 2014 5:58 am

Bruce Taylor wrote:Nice video. Usually, these guys are identified by the arrangement of the stalk and the myoneme (spasmoneme), the long fibre which gives the stalk its ability to contract. Vorticella and Pseudovorticella have non-branching stalks, so they contract individually, even when clustered together in a big group. In Carchesium, Pseudocarchesium and Zoothamnium, large numbers of zooids (the bell-shaped cells) can share a myoneme, so they will contract together. In Carchesium and Pseudocarchesium, that myoneme is discontinuous (that is, it does not run from side groups into the "main trunk" of the colony), so parts of the colony will contract independently. In Entziella and Myoschiston, it is partially continuous (stopping short of the main trunk), and in Zoothamnium it is continuous. In Carchesium, the contraction is spiral (as in Vorticella), while in Pseudocarchesium it is "zigzag," like an accordion. (For more, see Curds et al, British and Other Freshwater Ciliated Protozoa, 196 ff.)

To be sure of the identification, here, we'd need to have a good close look at the stalks, to determine whether the myonemes are continuous or not. Does the main trunk contract along with the side groups? It's hard to tell, in this case. Also, we'd want to have clearer footage of the contractions, to confirm that they are spiral (as I suspect) and not "zigzag."

Hi Bruce,

I very much appreciate your lengthy and informative reply. If I run into this organism again, I will make an effort to get more definitive video of the stalks and the contractions. I wasn't really thinking of what might be needed for identification when I made this video, but I'll do better next time.

From what I can see, the stalks and common stalks don't look like Zoothamnium. When I viewed all the footage, not just what I put in the video, I think I can see spiraling contractions as opposed to zigzag, so that seems to make Carchesium a pretty likely candidate.

Bruce Taylor · Post by **Bruce Taylor** » Mon Jun 23, 2014 7:08 am

billporter1456 wrote:
Bruce Taylor wrote:so that seems to make Carchesium a pretty likely candidate.
Yup. From what we see of the myoneme, it looks "sinusoidal" (like a shallow sinus wave running down the stalk), as in Carchesium. That arrangement produces the corkscrew contraction of the Vorticellidae.