Compare

Aulacoseira nygardii differs from A. nivaloides by the higher density of striae and areolae on the mantle and by the plain valve face. It differs from A. coroniformis by the absence of areolae on valve face.

LM scalebar = 10 µm
Aulacoseira nygaardii LM1 Aulacoseira nygaardii LM2 Aulacoseira nygaardii LM4 Aulacoseira nygaardii LM5 Aulacoseira nygaardii LM3 Aulacoseira nygaardii LM6 Aulacoseira nygaardii LM7
Diameter
4-11 µm
Width Range
4-19 µm
Striae in 10 µm
22-31

Aulacoseira nivaloides

(Camburn) English and Potapova 2009

Aulacoseira nivaloides LM3 Aulacoseira nivaloides LM2 Aulacoseira nivaloides LM6 Aulacoseira nivaloides LM7 Aulacoseira nivaloides LM1 Aulacoseira nivaloides LM5 Aulacoseira nivaloides LM4
Diameter
4-11 µm
Width Range
4-7 µm
Striae in 10 µm
14-22

Also compare to

Aulacoseira coroniformis

Pearce & Cremer