In todays post, we will be exploring one of the many forms “Scenedesmus” can come in. The genus Scenedesmus is a chlorophyte, a green alga, that can be solitary (rarely) or in a colonial form. There are many species of Scenedesmus, each taking on a slightly variable orientation or minute change in structure that alters the characteristics of the species. Some species have long spines originating from the corners of the top and bottom cells, while some have short spines on the sides of the inner cells. These tiny changes, along with the variability in cell size can determine exactly what species Scenedesmus can be. Below, find part of the dichotomous key to see how different individual cells can be.
Algaebase has the original publication of Scenedesmus (Meyen, 1829) in a PDF format that is definitely worth the download. With the use of molecular data along with gene sequencing, many Scenedesmus’ have been switched into Acutodesmus, Scenedesmus, or Desmodesmus. I have high confidence that there will be many more genus swapping using the newest technology at hand. But, this is all good news; thus it means that people are doing extensive research, which is always a good thing!
Lets take a look at some of the key features of what defines this species (The Freshwater Algal Flora of the British Isles):
- Coenobia of 2, 4 or 8 (more rarely 16 or 32) cells in a single linear row
- Cells (2-)3.5-9 um wide, (3.5-)7-21(-23) um long
- Cells ovoid, ellipsoidal or cylindrical, outer wall slightly convex, with apices broadly rounded, without ornamentation.
Science Thursday 