is this the diatom Planktoniella sol ?

[Franz Neidl]

I have never seen Planktoniella sol, therefore maybe I am completely wrong with this identification. The alga had a diameter from 100 µm and the "envelope" from about 200 µm.
I would be happy if somebody could help me.
2 pictures: obj. 20x (crop) and obj. 40x, DIC

Franz

[BJ]

Hello Franz,

I think that this is the dinoflagellate Pyrocystis noctiluca - not uncommon with me here in Portugal.

best wishes,

Brian