Stephanocyclus guide
  1. Central fultoportulae present
  2. Satellite pores (3) on central fultoportulae
  3. Marginal fultoportulae positioned on costae
  4. Rimoportula positioned on a costa

The genus is distinguished by features of the fultoportulae and rimoportulae. First, central fultoportulae are present, with three satellite pores. Second, marginal rimoportulae are positioned on a costa, between the valve face and valve mantle. Rimoportulae are located within the ring of marginal fultoportulae.

Stephanocyclus contains species that had included with Cyclotella meneghiniana and its allies. Many Stephanocyclus species, however, had not been formally transferred until recently (Kulikovskiy et al. 2022). Based on molecular data, Cyclotella gamma, Cyclotella meneghiniana, and Stephanocyclus planum are now considered within the genus Stephanocyclus.