Psammothidium scoticum differs from P. daonense and P. ventralis by its linear-elliptical shape. Valves of P. daonense are larger and elliptical, while valves of P. ventralis are more gibbous with wide subrostrate to subcapitate ends. P. acidoclinatum differs from P. scoticum by its wider axial area on rapheless valve and elliptical-lanceolate valve shape. Both P. acidoclinatum and P. ventralis have lower striae density than P. scoticum.

LM scalebar = 10 µm
Gsl00810 15A Ed Gsl00810 15B Ed Psammothidium scoticum LM2 Psammothidium scoticum LM3 Psammothidium scoticum LM2 Psammothidium scoticum LM1
Length Range
7.5-12 µm
Width Range
3.9-4.6 µm
Striae in 10 µm

Psammothidium acidoclinatum

(Lange-Bert.) Lange-Bert. 1996

Psammothidium acidoclinatum LM5 Psammothidium acidoclinatum LM4 Psammothidium acidoclinatum LM3 Psammothidium acidoclinatum LM2 Psammothidium acidoclinatum LM1
Length Range
8-16 µm
Width Range
4.4-5.8 µm
Striae in 10 µm

Psammothidium daonense

(Lange-Bert.) Lange-Bert. 1999

Psammothidium daonense LM3 Psammothidium daonense LM2 Psammothidium daonense LM1 Gs100739  Psdao 4A Ed Gs100739  Psdao 4B Ed Mo000019 1A Ed Gs007601  Psdao 1A Ed
Length Range
9-23 µm
Width Range
4.8-7.5 µm
Striae in 10 µm

Also compare to

Psammothidium ventralis

(Krasske) Bukht. and Round

BioData Reference
Krammer and Lange-Bertalot 2/4 Pl 24 Fig 8-22