Compare

Differentiation from Psammothidium altaicum and P. rechtense can be difficult. The raphe valves of P. rossii have a narrow, rectangular central area, while P. rechtense has a lanceolate central area and P. altaicum has an elliptic central area. In general, rapheless valves of P. rossii have a more narrow axial area than P. altaicum, but distinguishing rapheless valves of P. rossii and P. rechtense may not be possible. Psammothidium subatomoides has a bow-tie central area, rounded apices and the frustule is not flexed. Psammothidium biorettii is larger and has a larger central area. The raphe valve of Eucocconeis lapponica has a larger, asymmetric central area.

LM scalebar = 10 µm
Psammothidium rossii LM6 Psammothidium rossii LM4 Psammothidium rossii LM1 Psammothidium rossii LM7 Psammothidium rossii LM5
Length Range
9.7-11 µm
Width Range
4.8-5.7 µm
Striae in 10 µm
28-32

Psammothidium subatomoides

(Hust.) Bukht. and Round 1996

Psammothidium subatomoides LM10 Psammothidium subatomoides LM2 Psammothidium subatomoides LM4 Psammothidium subatomoides LM6 Psammothidium subatomoides LM8
Length Range
5.5–11 µm
Width Range
3.2-6.0 µm
Striae in 10 µm
30-40

Psammothidium bioretii

(Germain) Bukht. and Round 1996

Psammothidium bioretii LM3 Psammothidium bioretii LM2 Psammothidium bioretii LM1 Mo000019 1A Ed 3 Mo000019 1B Ed Gs028733  Psbio 1A Ed Gs028733  Psbio 1B
Length Range
12-26 µm
Width Range
5.3-9.1 µm
Striae in 10 µm
23-27

Also compare to

Eucocconeis lapponica

BioData Reference
Simonsen 1987 Pl 123 Fig 1-10

Psammothidium altaicum

(V.S.Poretzky) Bukht. in Bukht. and Round

BioData Reference
Krammer and Lange-Bertalot 2/4 Pl 20 Fig 24-32

Psammothidium rechtense

(Leclercq) Lange-Bert.