Caloneis amphisbaena and Mystery

[rnabholz]

Another nice Caloneis and a new one that I cannot ID yet. It is possible that this is a girdle view and that is what is leading me astray, but it sure is a real beauty! Any ideas or help on the ID is very welcome.

AO 10, Ortho Illuminator, 100x Oil iris, 214 darkfield condenser, Canon 70D Single frames

Caloneis amphisbaena 74µm

Caloneis 0138.JPG (48.86 KiB) Viewed 4152 times

Mystery Diatom 54µm

Diatom 0156.JPG (78.9 KiB) Viewed 4152 times

[vasselle]

Bonjour
Très belles séries images
Cordialement seb

[rnabholz]

Bonjour
Très belles séries images
Cordialement seb

Merci beaucoup Seb.

[molehill]

rnabholz nice images, BTW is your 70D on a stand separate from your microscope or attached to the microscope?
When I tried my new 70D last year the results where not good it vibrates in a way the 40D doesn't even in silent mode.

molehill

[rnabholz]

Mine is attached directly.

The only issues I have seen were related to the stability of my bench to touches by me during exposure.

I originally had a 60D, which I discovered was quite bad with vibration. The 70D is much, much quieter in that respect.

The 70D seems to be working well.

Rod

[mrsonchus]

Superb pictures Rod, both are fascinating.

[KurtM]

Hmmm, looks familiar ... why, a lot like the bright field shot molehill posted yesterday. He was calling it possible Achnanthidiun, although I haven't been able to find much on it.

See: viewtopic.php?f=6&t=3350

At any rate, it's a great image, and if it's a single frame, must be pretty flat. Where's exmarine when ya need him???

EDIT: Just ran across Rhopalodia gibba, shows possibility: http://westerndiatoms.colorado.edu/taxa ... odia_gibba

[rnabholz]

Hmmm, looks familiar ... why, a lot like the bright field shot molehill posted yesterday. He was calling it possible Achnanthidiun, although I haven't been able to find much on it.

See: viewtopic.php?f=6&t=3350

At any rate, it's a great image, and if it's a single frame, must be pretty flat. Where's exmarine when ya need him???

EDIT: Just ran across Rhopalodia gibba, shows possibility: http://westerndiatoms.colorado.edu/taxa ... odia_gibba

By golly, I think you have it! The only thing that is a question is the length, mine at 54um doesn't get to the low end of size range of 75 to 205 they quote, but let's just call mine an underachiever.

Also note that they say it is often seen in girdle view. Now that I know what I am looking at, I am pretty sure I have seen this in valve view as well in this sample.

Well played Kurt. Thanks

Rod

[KurtM]

That makes two that I am quickly becoming fascinated by (this week): Rhopalodia gibba and the Amphora genus, as they both seem to have been elusive of ID mostly due to the unusual trait of being seen most often in girdle view(?). I'm not too concerned about the small size ... and like you say, it's probably just a little bitty baby diatom, how cute!

Kociolek, P. (2011). Rhopalodia gibba. In Diatoms of the United States. Retrieved July 06, 2016, from http://westerndiatoms.colorado.edu/taxa ... odia_gibba

Spaulding, S. (2011). Amphora. In Diatoms of the United States. Retrieved July 06, 2016, from http://westerndiatoms.colorado.edu/taxa/genus/amphora

PS: I think I'll start C&P'ing the Cite This Page info, as above, instead of just the URL to give proper credit to an incredible resource.

[rnabholz]

That girdle view thing does make it hard on a guy....

Amphora ovalis was reasonably common on some of those slides I sent you, and seen in both orientations. That was how I first stumbled on the concept of girdle vs valve views. Not that I have readily incorporated it into my ID process, it still tends to be a last resort consideration. I think that is because most references don't include girdle views unless it is commonly seen.

Agree about citing link. I would be lost without that site.

[rnabholz]

Superb pictures Rod, both are fascinating.

Thanks John

[gekko]

Both are beauties, with images to match.

[rnabholz]

Thanks Gekko