The triradiate, monospinous desmid Staurodesmus mucronatus in frontal view (semicell lobes facing the observer are out of focus)

Cell dimensions (L x B, including spines): ca 25 x 35 µm


Desmid of the month
November 2004

Staurodesmus mucronatus

The genus Staurodesmus was established by Teiling (1948) by fusing parts of the genera Arthrodesmus and Staurastrum. Species of Staurodesmus are marked by smooth-walled semicells which in apical view are bi- to pluriradiate, and furnished with one single spine per radius. S. mucronatus belongs to a group of species which usually are triradiate (formerly alotted the genus Staurastrum)*.  In frontal view, S. mucronatus is characterized by  ellipsoid semicells bearing  a rather short, horizontal or slightly upwards projected spine at each of the poles. In the Netherlands it is a rather rare species, occurring in benthos of slightly acidic, mesotrophic water bodies.

Staurodesmus mucronatus in apical view, showing an axile chloroplast with forked lamellae extending into each of the three semicell lobes.

* For an example of a biradiate Staurodesmus species, see Staurodesmus convergens.


Teiling, E., 1948. Staurodesmus, genus novum. — Botaniska Notiser 1948: 49-83.