Compare

Psammothdium semiapertum differs from P. pennsylvanicum by lower areola density (25 vs 35-40 in 10 μm).

LM scalebar = 10 µm
Psammothidium semiapertum LM5 Psammothidium semiapertum LM4 Psammothidium semiapertum LM1 Psammothidium semiapertum LM3 Psammothidium semiapertum LM2 Psammothidium semiapertum LM6
Length Range
8.5-10.4 µm
Width Range
4.4-5.2 µm
Striae in 10 µm
22-24

Psammothidium pennsylvanicum

Potapova 2012

Psammothidium pennsylvanicum LM2 Psammothidium pennsylvanicum LM1 Psammothidium pennsylvanicum LM6 Psammothidium pennsylvanicum LM5 Psammothidium pennsylvanicum LM4 Psammothidium pennsylvanicum LM3
Length Range
9–13 µm
Width Range
5.0–5.4 µm
Striae in 10 µm
25–29