Compare

Psammothidium daonense valves are larger and elliptic.

Psammothidium ventralis valves are more gibbous, with wide subrostrate to subcapitate ends, and lower stria density.

Psammothidium acidoclinatum has a wider axial area on the rapheless valve, an elliptic-lanceolate valve shape, and lower stria density.

Psammothidium sacculum has less linear valves, a narrower axial area, central area on raphe valve
bordered by striae of alternate length, smaller central area on rapheless valve, and larger areolae (visible in LM).

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
27-30

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
24-30

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
23-27

Psammothidium sacculum

(J.R. Carter) Bukhtiyarova 1996

Psammothidium sacculum LM5 Psammothidium sacculum LM3 Psammothidium sacculum LM4 Psammothidium sacculum LM6 Psammothidium sacculum LM2 Psammothidium sacculum LM7 Psammothidium sacculum LM1
Length Range
8-13 µm
Width Range
3.9-4.4 µm
Striae in 10 µm
26-30

Also compare to

Psammothidium ventralis

(Krasske) Bukht. and Round

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