Phylum: Charophyta   Family: Desmidiaceae

Staurastrum longipes var. contractum E. Teiling 1946

Differs from the nominate variety in having broadly triangular semicells, which are shorter in length, with almost straight sides giving rise to an open, acute, sinus. The long processes are tipped with four stout spines. Cells are mainly 3- and 4-radiate.
Overall cell dimensions: L: 62-83 µm; B: 80-109 µm; Is: 7.8-9.9 µm.
Even scarcer than the nominate variety with few recent records. It seemingly occupies the same Atlantic regions, in mesotrophic waters.

References: 
Coesel, P.F.M. & Meesters, K.J. (2013). European Flora of the Desmid Genera Staurastrum and Staurodesmus.