Alga(flagellate) for ID please

[jc maccagno]

Pond water 40X and 100x

[carlos.uruguay]

Without any safety, Chlamydomonas actinochloris?
carlos

[BJ]

Hi John e Carlos,

i think that I can see 4 flagella in the first photo and a suggestion of more than two in some of the other photos.

If this is correct, then it cannot be a Chlamydomonas (which has two flagella) unless it is a cell in some reproductive stage. Carteria is very similar to Chlamydomonas but does have 4 flagella.

However, I would like to suggest (but, like Carlos, without confidence) that this is a species of Scherffelia and maybe Scherffelia dubia. This alga is rather variable in outline but sometimes rather lobed as in this specimen. It has two separate chloroplasts and 4 flagella. It has a covering of minute scales (need an electron microscope) and not a cellulose cell wall. The genus is very close to Tetraselmis and is classified in the Prasinophyta or Chlorodendrophyceae. Scherffelia dubia is an alga of ponds and stagnant waters. Your specimen is large for this species, but I see on the web that there are a variety "major" and a forma "maxima" listed.

boa sorte
Brian

[carlos.uruguay]

Thank you so much Brian.
I had not seen the 4 flagella!

[René]

My usual suspect would be Cryptomonas, not doing well.

Best wishes, René

[jc maccagno]

Many thanks for all of your suggestions; My observations: A very healthy specimen active swimming and 4 flagellae (appeared lilke 2 from each lobe)

Thank you

john

[BJ]

René,

Scherffelia dubia was originally thought to be a cryptophyte ....Cryptomonas dubia (Perty 1852)... so you were justified....

Please remember that my identification is anyway only tentative.

best wishes,

Brian