"no idea" nr.4 (Umbilicosphaera cfr. sibogae)

[Franz Neidl]

not a beautiful picture... but I am too much interested in knowing what kind of living organism it is.
marine plankton
It was 50 µm long
objectiv 40x, DIC.
2 pictures

Franz

[Cactusdave]

I'm thinking Radiolarian for that one. I've seen very similar empty shells in marine sediment and fossil marine deposit samples.

[BJ]

Hi Franz and Dave,

I think that it is too small and the outline too rough to be a radiolarian. Without the outer shell, I think that you would identify the pigmented bodies as algal cells.

My guess is that this is a dividing coccolithophore. Pushing this potential identification to the absolute limit I propose Umbilicosphaera sibogae. There are images here:

http://www.biol.tsukuba.ac.jp/~inouye/i ... _pic2.html

- which look very like (half of) your specimen to me.

boa sorte
Brian

[Franz Neidl]

Thank you Dave and Bryan for your help!
I too had doubths about the green colour of the algae. I think the best solution is Umbilicosphaera. I found now an interesting site about it from the Stazione Zoologica Anton Dohrn in Napels:

http://www.szn.it/SZNWeb/cmd/ShowArchiv ... GUAGE_ID=2

Franz

[BJ]

Hi Franz,

the photo from SZ Anton Dohrn leaves no doubt, your specimen is its twin !

If you get a specimen again, or other coccolithophores, it would be interesting perhaps to dry the slide out and then re - wet with distilled water to see if you could dislodge some of the coccoliths and take photos of them. Useful photos will probably need the oil immersion lens. These days all the photos of coccoliths are taken with the SEM. I would love to see what a skilled microscopist/photographer like yourself (and others!) could do with the light microscope.

my challenge for you !

thank you for another fascinating organism,
best wishes,
Brian