Bullseye

Or two actually. That is what I see here - a young bull running around on the green, green grass of his first spring, looking curiously around for the wonders of the world:

But then again, not many people have told me I lack imagination.
Others just call this algae Mesostigma viride. Me too, when counting.

The young bull expression comes from the two pyrenoids on each side of the cell and the ”lightly saddle-like bent” body, as Skuja (1948) describes the form of the cell.

The flatness of the cell supports the impression of the saddle:

What also catches the eye is the square-like-structure on the cell:

For the squares a high N.A. for the objective and condensor is recommended. It is quite small, the whole cell is only about 10 µm "big".

The flagella, on the other hand, are more seldom seen in fixed samples. They emerge from the ventral side of the cell, not apical or from the side, as in most other algae.

Also the stigma is not so clearly seen in lugol samples. The stigma should be a big one and in the middle of the cell - that's why Lauterborn gave it the name Mesostigma.

Mesostigma has earlier been regarded as a member of Prasinophyta, so being in the oldest group of green algae, going back perhaps all the way to PreCambrian (Moestrup 2002). This algae has been a subject to intensive taxonomical studies and a has finally gotten a whole Class of it's own: Mesostigmatophyceae in Streptophyta, (Marin & Melkonian 1999, Leliaert et al 2012). So not in Chlorophyta. AlgaeBASE still uses terms as Prasinophyte and Charophyta, strange.

I have seen these algae in a couple of samples in Finnish waters. Once you get the picture of it in your brain, it's very easy to identify. Although this time the drawings in the books are not very helpful. Even Skuja's drawing is this time not quite accurate:

Skuja, H. (1948).

Try to find it, it is there, waiting for you in many kinds of fresh waters.


Literature:

Lauterborn, R. (1894). Ueber die Winterfauna einiger Gewässer der Oberrheinebene. Mit Beschreibungen neuer Protozoen. Biologische Centralblatt 14: 390-398.
http://www.algaebase.org/pdf/562DFCAF13e03286E3uGv3A26EC8/48540.pdf

Marin, B. & Melkonian, M. (1999). Mesostigmatophyceae, a new class of streptophyte green algae revealed by SSU rRNA sequence comparisons. Protist 150: 399-417, 9 figs, 2 tables.

Skuja, H. (1948). Taxonomie des Phytoplanktons einiger Seen in Uppland, Schweden. Symbolae Botanicae Upsalienses 9 (3). A. -B. Lundequistska Bokhandeln, Uppsala, 399 pp., XXXIX pls.

Leliaert F., Smith D.R., Moreau H., Herron M.D., Verbruggen H., Delwiche C.F. & De Clerck O. Phylogeny and molecular evolution of the green algae. (2012) Critical Reviews in Plant Sciences 31: 1-46.

Foldscope

Foldscope is coming!
Soon the microscopic world is within reach to everybody. And not only for fun, but for the benefit of all mankind. I'm happy to be involved in this project.

Like they say:
"Finally, we are as excited about scaling up this project as you are about using and sharing the microscopic world with everyone. We hope to build a community that grows with time, is passionate about teaching each other the mysteries of the microscopic world and finally has empathy towards the divide that exists in access to scientific tools and wants to contribute positively towards eliminating the same."

Take a look at this great project: http://www.foldscope.com/

Read more:
Foldscope: Origami based paper microscope
J. Cybulski, J. Clements and M. Prakash
PLoS ONE 9(6):e98781. doi:10.1371/journal.pone.0098781,June 2014

Nephrochlamys allanthoidea Korshikov 1953

In two samples a lot Nephrochlamys-cells. Were they really N. allanthoidea instead of the more common N. subsolitaria (nowadays N. rostrata, according to Nygaard, Komárek, J.Kristiansen & O.M.Skulberg 1986 (which I have not yet had the pleasure of reading - you can throw a copy this way, if you are passing by))?

If all goes well, N. allanthoidea very easy to identify. One can see the short, blunt wing-like extensions on the sides of the mother cell, like here in the original drawing of Korshikov.

Korshikov 1953

But sometimes it does not have them. I'd say, keep on looking, for other individuals. On the other hand the drawings in both Komárek & Fott 1983 and Hindák 1984 you can see that also N. subsolitaria can have mother cells with extensions. A bit smaller, and different -yes. But this does mean that one should not rush to baptize the thing to allanthoidea only because of some little wings.

What then? You can also take a look at the shape of the cells. According to Hindák (1984, 1988) the cells are less bent than in the other Nephrochlamys-species. Ok, but in my samples the cells were quite bent. Is this allowed? At least the ends of the cells were equal, not one pointed and another sharp, as N. subsolitaria/rostrata has it.

Yet another identifyication point in N. allanthoidea is the number of autospores: according to Komárek & Fott 1983 4-(8), while N. subsolitaria/rostrata has only four. But then again, Hindák (1988) mentions for N. allanthoidea, that "only four autospores were formed". This does of course not rule out that there could be 8, like Komárek & Fott said.

In my samples I saw mother cells holding more than 4 autospores in it, and that should be characteristic to allanthoidea.

So I would say, that these are N. allanthoidea, in spite of the curved cells. What do you think?





Literature:

Hindák, František 1984. Studies on the chlorococcal algae (Chlorophyceae). III. Biol. Práce., XXX/1, p. 308.

Hindák, František 1988. Studies on the chlorococcal algae (Chlorophyceae). IV. Biol. Práce., XXXIV/1-2, p. 264.

Komárek, J. & Fott, B. (1983): Chlorophyceae (Grünalgen). Ordnung: Chlorococcales. - In: G. Huber-Pestalozzi (†). Das Phytoplankton des Süßwassers. Systematik und Biologie. 7. Teil, 1. Hälfte. In: Elster, H.-J. & Ohle, W. (red.). Die Binnengewässer. Einzeldarstellungen aus der Limnologie und ihren Nachbargebieten. Band XVI. E. Schweizerbart’sche Verlagsbuchhandlung (Nägele u. Obermiller), Stuttgart. X + 1044 pp., incl. 253 pls. ISBN 3-510-40023-2.

Korshikov, O. (1953). Viznachnik prisnovodnihk vodorostey Ukrainsykoi RSR [Vyp] V. Pidklas Protokokovi (Protococcineae). Bakuol'ni (Vacuolales) ta Protokokovi Protococcales) [The Freshwater Algae of the Ukrainian SSR. V. Sub-Class Protococcineae. Vacuolales and Protococcales]. pp. 1-439. Kyjv [Kiev]: Akad. NAUK URSR.

Nygaard, G., Komárek, J., Kristiansen, J. & Skulberg, O.M. (1987 '1986'). Taxonomic designations of the bioassay alga NIVA-CHL 1 ("Selenastrum capricornum") and some related strains. Opera Botanica 90: 1-46, 35 figs, 9 tables.