Cell of Cosmarium denboeri in apical view. Notice strong, median inflation of the semicell.

Cell of Cosmarium denboeri in frontal view. Notice oblong semicells with slightly produced apex.

Cell dimensions (L x B): 20 x 20 µm



Desmid of the month
February 2016

Cosmarium denboeri

C. denboeri is a small-sized, inconspicuous Cosmarium species. Cells are about as long as broad with a deep sinus that usually opens about halfway. Semicells are elliptic-oblong in outline, the apex usually slightly produced. The centre of the semicell is abruptly inflated and furnished with a group of small granules. At the semicell margin and just within it also a series of distant, acute granules/dentations. C. denboeri (named after our webmaster, Kees den Boer) was only recently described*, but in the Netherlands it appears to be widely distributed in plankton of eutrophic, alkaline water bodies.

* Meesters, J. & Coesel, P.F.M., 2007. Cosmarium denboeri: een nieuwe, planktonische sieralgsoort met een potentieel groot verspreidingsgebied. Gorteria 32: 144-147.

Dead cell of Cosmarium denboeri well showing produced apices and dentate margins.

SEM picture of Cosmarium denboeri showing cell wall sculpturing in detail.