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Psammothidium lauenburgianum has a rimmed depression on the rapheless valve like many species of Planothidium. It is most likely to be confused with Planothidium lanceolatum, but can be distinguished from it by considerably higher stria density.

LM scalebar = 10 µm
Psammothidium lauenburgianum LM5 Psammothidium lauenburgianum LM4 Psammothidium lauenburgianum LM1 Psammothidium lauenburgianum LM3 Psammothidium lauenburgianum LM2 Psammothidium lauenburgianum LM6 Psammothidium lauenburgianum LM7
Length Range
8.0–14.0 µm
Width Range
3.5–5.0 µm
Striae in 10 µm
24–28

Planothidium lanceolatum

(Bréb. ex Kütz.) Lange-Bert. 1999

De000084 6 De000084 4 De000084 7 Ih042040  Pllanc2 Ih042040  Pllanc4 Ih042040  Pllanc1 Mo000019 1
Length Range
7-24 µm
Width Range
4.5-8.0 µm
Striae in 10 µm
12-15