Dinobryon acuminatum Ruttner, 1913
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Dinobryon acuminatum
Diagnosis:
- individuals solitarily
lorica vase-shaped with tapered stalk, 30–38 µm long
upper half of lorica cylindrically, slightly wavy - lower part of lorica slightly widened and wavy
- two flagella of different lengths
- two contractile vacuoles in midbody
- 1–2 golden brown colored chloroplasts
- apical eyespot present
- one spherical nucleus between chloroplasts
- below chloroplasts a crysolaminarin body
Dinobryon acuminatum is a solitary species of the genus. So far I have only found a few specimens in the Simmelried. Huber-Pestalozzi (1941) mentions that Dinobryon acuminatum is a spring form with a vegetation period of only 6 weeks. The optimum temperature for this species appears to be 8 °C. Skuja (1955) mentions that he found the specimens swimming freely (plankton?).
The lorical of Dinobryon acuminatum can be easily recognized by its cylindrical upper half. The opening of the lorica is not funnel-shaped widened. Below the cylindrical part, the lorica widens and then turns into a tapering stalk.
The number of chloroplasts is given differently by the earlier authors. According to Huber-Pestalozzi (1941) there should be two, while Skuja (1955) mentions only one chloroplast. According to my observations, it is only one chloroplast that surrounds the nucleus.
Fig. 1 a-b: Dinobryon acuminatum. L = 42 µm (of lorica). Two focal planes of a specimen attached to a detritus flake. Note the cylindrical upper part of the lorica. The aperture is not widened. CV = contractile vacuole; F1, F2 = flagella, Nu = nucleus. Obj. 100 X.