Staurastrum simonyi var. sparsiaculeatum

(Schmidle) Hirano, 1953

Most likely ID: n.a.

 

Synonym: Staurastrum sparseaculeatum

 

Sampling location: Paradieswiesen (Austria)

 

Phylogenetic tree: Staurastrum simonyi var. sparsiaculeatum

 

Diagnosis: 

  • cells about as long as broad
  • semi-cell elliptic
  • apices convex
  • length 20–29 µm, width 21–30 µm
  • sinus open and acute angled
  • lateral angles with with two spines directed toward cell equator
  • cell wall with 2–3 horizontal rows of spines
  • in apical view 3 axis, sometimes 4
Staurastrum-simonyi-var-sparsiaculeatum
Staurastrums simonyi var. sparsiaculeatum

So far I have found Staurastrum simonyi var. sparsiaculeatum only once in June 2024 in the Paradieswiesen in Austria. This desmid algae seems to be generally rare. Apparently, Lenzenweger (1997) also found specimens only once in samples from Obergurgl (Austria).

 

Staurastrum simonyi var. sparsiaculeatum shows a high degree of variability, which does not make identification any easier. The spines on the cell surface can vary in length. My variety is most similar to the drawings by Schmidle (s. drawing 1 above), which shows a form with short spines. The most striking features are the horizontal rows of spines  (s. fig. 1 a) and the spines on the lateral angles, which are always directed towards the cell equator (s. fig. 1 b).

Staurastrum-simonyi-var-sparsiaculeatum

Fig. 1 a-d: Staurastrum simonyi var. sparsiaculeatum. L = 26 µm. Different focal planes of a specimen with short spines. Note the spines on the lateral angles, which are directed towards the cell equator (arrows). Obj. 100 X.