Euglena deses

(O.F. Müller) Ehrenberg, 1834

Most likely ID: n.a.

 

Synonym: Euglena intermedia, Euglena klebsii

 

Sampling location: Simmelried

 

Phylogenetic tree: Euglena deses

 

Diagnosis:

  • cell elongated cylindrically with almost parallel sides
  • posterior end tapered to short point
  • anterior end blunt
  • length 62–229 µm
  • euglenoid movement
  • flagellum short, one-sixth to one-third of body length
  • numerous chloroplasts, disc-shaped, pyrenoids present or absent
  • large paramylon grains, oblong shaped
  • pellicle faintly striated
  • nucleus central
  • eyespot red, conspicuous
Euglena-deses
Euglena deses

In 2011 Karnkowska-Ishikawa et al. united the species Euglena deses, Euglena intermedia and Euglena klebsii under Euglena deses on the basis of morphological and genetic studies. This union also includes all the varieties described within the species Euglena intermedia and Euglena klebsii.

 

So far I have only been able to find Euglena deses in the Simmelried. The species stands out due to its elongated, cylindrical shape with a short tip. However, a reliable classification can only be made by closely examining the chloroplasts. In Euglena deses they are disc-shaped with or without a pyrenoid.

 

All the specimens I observed were larger than 150 µm. Some specimens even had a length of 180 µm. In my population, none of the chloroplasts had a pyrenoid (s. fig. 4).

Euglena-deses

Fig. 1 a-f: Euglena deses. L = 179 µm. Different phases of the euglenoid movement. Obj. 40 X.

Euglena-deses

Fig. 2 a-b: Euglena deses. L = 158 µm. Two focal planes of a slightly squashed specimen. Note the pointed posterior end (PE). The flagellum (F) of this specimen has a length of about 50–60 µm. Obj. 40 X.

Euglena-deses

Fig. 3 a-c: Euglena deses. L = 162 µm. A slightly squashed specimen in detail. The flagellum was already shed off. ES = eyespot, RE = reservoir. Obj. 100 X.

Euglena-deses

Fig. 4 a-c: Euglena deses. Three focal planes on the faint striation of the pellicle (SP), the disc-shaped chloroplasts (Chl) without pyrenoid and the oblong shaped paramylon grains (PG). Nu = nucleus, RE = Reservoir. Obj. 100 X.