Staurastrum anatinum
image © Chris Johnson (after Scottish material)


Staurastrum anatinum (var. anatinum). Notice cup-shaped semicell body with long processes that are tipped with stout spines.
Cell dimensions (L x B): ca 50 x 90 µm



Staurastrum anatinum
image © Chris Johnson (after Scottish material)

Cell of St. anatinum in apical view. Notice submarginal dentations on semicell body.


St. anatinum
image © Matthijs Koek

St. anatinum var. subanatinum in apical view. Notice long, bifurcate spines at the margins of the semicell body characteristic of this variety (mouse-over).

 


Desmid of the Month
July 2025

Staurastrum anatinum


Staurastrum anatinum is a rather large-sized, triradiate species characterized by long, parallel to divergent processes tipped with 2-4 stout spines. Its semicell body in frontal view is subfusiform to cup-shaped and ornamented with two series of acute granules/verrucae/denticulations or spines: one apical and one subapical-median series. St. anatinum is a planktic species occurring in acidic, oligo-mesotrophic lakes and pools. In the Netherlands, the nominate variety has not been found for decades; its var. subanatinum, however, was encountered for the last time in 2023 (in Belgian Flanders, near the Dutch border).


Staurastrum anatinum
Image © Robin Matthews (after North American material)

SEM picture of St. anatinum showing in the upper semicell body an apical and a subapical-median series of acute granules.

Staurastrum anatinum
Image © Roland Luts

St. anatinum var. subanatinum in frontal view.
Cell dimensions (L x B): 36 x 60 µm