Cosmarium crenatoides
image © Alfred van Geest

Cosmarium crenatoides in frontal view. Notice oblong cell outline and deep, marginal crenations. Notice also the upper lateral lobe being much larger than the lower ones. Cell dimensions (L x B): 37 x 27 µm

Cosmarium crenatoides
image © Alfred van Geest

Cell of C. crenatoides in lateral view. Notice basal part of semicells being distinctly inflated.

Cosmarium crenatoides
image © Marien van Westen

SEM picture of C. crenatoides showing cell wall ornamentation in detail.



 


Desmid of the Month
February 2026

Cosmarium crenatoides


In cell outline and deeply crenate margin Cosmarium crenatoides resembles C. neocrenatum but its cell wall ornamentation is more pronounced. Most important feature is the wide band of supraisthmial costae joining the inframarginal radiate series of granules in the basal, lateral crenations. Moreover, there is a distinct difference in size of the lateral crenations: the upper one being much larger than the lower ones. In the Netherlands, C. crenatoides is of incidental occurrence on wet substrates of natural or artificial nature.

Cosmarium crenatoides
image © Alfred van Geest

Semicell of C. crenatoides in apical view (a bit lemon-shaped).


Cosmarium crenatoides
image © Alfred van Geest

Empty cell of C. crenatoides in frontal view. Notice wide band of supraisthmial costae (actually longitudinal series of closely spaced granules).