Compare Cocconeis neodiminuta
Compare
Cocconeis pseudothumensis is easy to confuse with C. neodiminuta, because transitional forms may be observed. The valves of C. pseudothumensis are broadly-elliptic with rounded ends and the raphe valve has finer striae that are not resolvable with LM. The rapheless valve has a wider, elliptic-lanceolate axial area and relatively smaller, rounded areolae. Cocconeis disculus is larger, has coarser striae on the rapheless valve, and wider areolae on rapheless valve with different ultrastructure (see Stancheva 2018 for details and images). Cocconeis disculus is not yet confirmed in streams and rivers of California.
LM scalebar = 10 µm
Length Range
7-18 µm
7-18 µm
Width Range
5-9 µm
5-9 µm
Striae in 10 µm
Raphe valve 24-32, rapheless valve 11-14
Raphe valve 24-32, rapheless valve 11-14
Cocconeis pseudothumensis
.jpg)
Length Range
9-15.3 µm
9-15.3 µm
Width Range
6.9-10.6 µm
6.9-10.6 µm
Striae in 10 µm
rapheless: 10-14, raphe: 25-27 at margin, 38-40 near axial area
rapheless: 10-14, raphe: 25-27 at margin, 38-40 near axial area
Also compare to
Cocconeis disculus
BioData Reference
Krammer and Lange-Bertalot 2/4 PL 56 Fig1-13