Biremis ambigua (Cleve) D.G.Mann Figs 30, 31

Ref. illus.: Cox 1990, figs 19–28; Sabbe et al. 1995, figs 34, 35, 38, 51, 52; Witkowski et al. 2000, p. 158, pl. 155, figs 2–6; Tatarek & Wiktor 2005

Samples: GU52O-4

Dimensions: Length 38–54 µm, width ca. 6 µm; striae 9–10 in 10 µm

Diagnostics: Linear, symmetrical valve, similar in size and stria density to B. ridicula (see below), which is strongly asymmetrical.

Comments: Biremis is characterized by alveolate striae. Several smaller species have been observed but not yet identified.