Brachysira serians is greater in length and broader than B. neoacuta. In addition, the apices of B. neoacuta are distinctly apiculate. Large valves of B. superserians (known from Florida) can be confused with B. serians, but B. superserians has more more narrowly pointed apices. Brachysira subrostrata (known from Brazil) has a similar lanceolate valve to B. serians", but is smaller in length (<70 um) with distinct protracted apices. *Brachysira serians var. rostrata is smaller than B. serians with apiculate to subcapitate apices.

LM scalebar = 10 µm
Brachysira serians LM5 Brachysira serians LM4 Brachysira serians LM3 Brachysira serians LM2 Brachysira serians LM1
Length Range
50-123 µm
Width Range
14-19 µm
Striae in 10 µm

Brachysira neoacuta

Lange-Bert. in Lange-Bert. and Gerd Moser 1994

Bracysira neoacuta LM7 Bracysira neoacuta LM6 Bracysira neoacuta LM5 Bracysira neoacuta LM4 Bracysira neoacuta LM3 Bracysira neoacuta LM2 Bracysira neoacuta LM1
Length Range
31-51 µm
Width Range
6.5-9 µm
Striae in 10 µm

Also compare to

Brachsira superserians

Metzeltin and Lange-Bert.

Brachysira serians var. rostrata


Brachysira subrostrata

Lange-Bert. in Lange-Bert. and Gerd Moser