Is this Diceras phaseolus? 40X 100X freshwater pond

[jc maccagno]

My only reference of the above organism describes a globe with a small circular pore surronded by a low collar. It can have two-three long tapering spines whose length are several times the diameter. The protoplast which is golden brown completely fills the lorica. There are 2 contractile vacuoles and several leucosin granules. Some of these features are present in these specimens. All help is appreciated. Thanks
John

[Bruce Taylor]

The picture and description in my copy of Fresh-water Algae of the United States (2nd edition, 1950, p. 432) gives some support to your identification, I think. The lorica shown there is more ovate, and has only two "horns." However, the description says the lorica may be "globose to reniform," and may have "two (occasionally three) long tapering spines." Also: "At times, the protoplasts may have two delicate cytoplasmic filaments projecting through the pore of the lorica." Your final picture does seem to show this.

I'll scan the pic, if you like.

A very interesting class of creatures, about which I knew nothing. Thanks for posting it!

[jc maccagno]

Thanks you for your comments.. Scanning the picture would be great.

Thanks for your interest

John

[Bruce Taylor]

Sorry for the delay...

[BJ]

Hi,

I think that there are three (and a bit) problems with identifying this as Diceras (now Bitrichia).

1. In Bitrichia, the spines are dead straight or gently curved not "wavy" as in your specimen.

2. In Bitrichia, the spines have a wide base.

3. the collar of the pore is narrow, not extended into a tube.

4 (the bit).. In Bitrichia, the chloroplast usually takes up most of the cell.


I would like to suggest an alternative identification:

I think that this is a stomatocyst (resting stage ) of the chrysophyte flagellate Ochromonas ostreaeformis. This has three narrow wavy spines, a tube-like pore, and a single chloroplast restricted to just part of the cell.

boa sorte
Brian

[uaalgae]

Yes, the genus was changed to Bitrichia (has a bulbous seta) and I also think this may be a statospore of a Chrysophyte.

[jc maccagno]

Many thanks to both of you for your comments. It is great that you experts are taking the time to comment on an amateur's postings

John

[uaalgae]

John,
We are all amateurs when it comes right down to it. I just know more trivia about the algae than most (only been studying and looking at algae for over 45 years).
Donald