Arcella, Nebela and friends -- images added

Cactusdave · Post by **Cactusdave** » Sun May 11, 2014 12:55 pm

There have been some wonderful posts here recently of live Arcella and other testate amoebae. My pictures I'm afraid are of dead specimens, but still interesting I hope. These are all from a set of slides made in 1994 by an amateur mounter in the UK and circulated to members by the Postal Microscopical Society, a venerable British institution, established in 1873 and still going! http://myweb.tiscali.co.uk/postalmicsoc/whatpms.html The mounts have deteriorated a little from a perhaps unwise choice of mountant, but still contain some fascinating specimens. They were all collected from Sphagnum moss squeezings from the North and West of England.

Photographed with DIC on a Nikon Diaphot with a Canon EOS 5D mk2 mounted at the front SLR port. There is a X2.5 relay lens in the light path. All with a Nikon Plan DIC X40 0.75 objective and a LWD 0.52 condenser. Single unstacked images.

I am no expert on testate amoebae, so am using the identification suggested by the mounter. Please correct or amplify my suggestions if you know better!

First some Arcellas.

These are all noted by the original mounter as probably Arcella vulgaris.

Not sure what I'm seeing here. It looks as though coverslip pressure has cracked open some kind of cyst or resting body. But what is coming out? Baby Arcellas, or something else entirely. Perhaps someone can tell me?

The greatest variety of specimens seem to be species of Nebela, but I'm open to correction of course.

The suggested ID for this one is Nebela collaris.

The next one is suggested to be Nebela flabellulum.

More tomorrow.

arturoag75 · Post by **arturoag75** » Sun May 11, 2014 1:31 pm

Amazing ahots

Cactusdave · Post by **Cactusdave** » Mon May 12, 2014 2:46 am

Thanks Arturo.

This is another example of Nebella collaris as identified by the mounter. The bubbles are a result of deterioration in the mountant.

This is clearly another Nebela, but looks a bit different with distinct round plates.

I felt sorry for this Nebela, trapped in a maze of shrinking mountant and cheered him up with a bit colour from "detuning" the DIC

Actually it helped with contrast as well. I think this is Nebela collaris again.

I think this is also Nebela collaris, again trapped by shrinking mountant.

Really not sure about this one. It looks like a Nebela, but quite different. Glad to have the advice of the experts.The extravagant 'plume' is caused by crystallization of salts in the mountant.

Final one today. I'm not even totally sure this is a Nebela at all, but the mounter has suggested Nebela carinata. Advice of the experts very welcome.

Still some nice Difflugia bacillifera and a Cyphoderia to come!

piermicro · Post by **piermicro** » Mon May 12, 2014 3:09 am

Really beautiful.

Jacek · Post by **Jacek** » Mon May 12, 2014 3:26 am

nice

Cactusdave · Post by **Cactusdave** » Mon May 12, 2014 1:43 pm

Thanks Jacek and piermicro. A few more pictures tomorrow.

Cactusdave · Post by **Cactusdave** » Tue May 13, 2014 2:16 am

Last set of images for this thread as promised.

First a final Nebela collaris. This one does show the composition of the test very nicely.

Here are a few examples of Difflugia bacillifera. This testate amoeba gets its name from its tendency to make its shell mainly or completely from species of diatom. I have converted the first two images to black and white. The mounter had stained the samples with methylene blue, and I found this distracting. The DIC does a good enough job of providing contrast without the need for stains.

I think this third example, from a different Sphagnum sample, is the same species, just a different choice of diatoms.

Finally something slightly different. This is Cyphoderia sp. probably Cyphoderia ampulla. This belongs to the filose section of testate amoebae as opposed to the lobose section to which all the others shown belong. Once again the shell has acted as a nucleus on which salts in the mount have unfortunately crystallized.