Desmodesmus brasiliensis
(Bohlin) Hegewald, 2000
Most likely ID: n.a.
Synonym: Scenedesmus brasiliensis
Sampling location: Lake Constance
Phylogenetic tree: Desmodesmus brasiliensis
Diagnosis:
- coenobia of (2)–4–(8), linearly arranged cells
- cells elongated oval to cylindrical
- length of cells 9–28 µm, width 2–8.5 µm
- (1)–2–4 longitudinal, continuos ridges per cell (sometimes absent)
- inner and outer cells with short teeth at the apices
- margins of the outer cells smooth
- one pyrenoid per cell
Desmodesmus brasiliensis was originally described by Bohlin (1897) as Scenedesmus brasiliensis, but was transferred to the genus Desmodesmus by Hegewald in 2000.
I have found Desmodesmus brasiliensis in the plankton of Lake Constance in July 1994. The main characteristics of Desmodesmus brasiliensis are the short teeth at the apices (s. fig. 1 a) and the continuous ridges along the lateral sides of the cells (s. fig. 1 b).
The very similar species Desmodesmus lefevrei (synonym = Scenedesmus lefevrei) can be distinguished from Desmodesmus brasiliensis by a fringe of small teeth at the margins of the outer cells (s. Michael Plewka-Freshwater life-Scenedesmus lefevrei).
Fig. 1 a-b: Desmodesmus brasiliensis. L = 19 µm (of coenobium). Two focal planes of a coenobium of 4 cells. Note the short teeth at the apices of the cells (a) and the continuous ridges on the sides of the cells (b). Obj. 100 X.