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Aulacoseira crassipunctata differs from other species of Aulacoseira by relatively large round mantle areolae that are relatively distant from each other, strongly concave or convex valve face, long collum, and the ringleiste that is bell-shaped in cross-section. A. crassipunctata sometimes was misidentified as A. canadensis, which is an extinct species. Unlike A. crassipunctata, A. canadensis has flat valve face, shelf-like ringleiste, and short collum.

LM scalebar = 10 µm
Aulacoseira crassipunctata LM6 Aulacoseira crassipunctata LM5 Aulacoseira crassipunctata LM3 Aulacoseira crassipunctata LM4 Aulacoseira crassipunctata LM1 Aulacoseira crassipunctata LM2
Diameter
4-12 µm
Width Range
9-18 µm
Striae in 10 µm
5.5-9

Also compare to

Aulacoseira canadensis

(Hust.) Simonsen