Psammothidium pennsylvanicum

Potapova 2012      Category: Monoraphid

Psammothidium nivale


Psammothidium scoticum

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - January 2012
Length Range: 9-13 µm
Width Range: 5.0–5.4 µm
Striae in 10 µm: 25–29


Valves are elliptic. Raphe valve has a narrow linear axial area and transversely rectangular, or elliptic central area. The raphe is filiform and straight with slightly expanded, almost straight or very slightly deflected external distal ends. The internal proximal raphe ends are deflected to opposite sides. The internal distal raphe ends have small helictoglossae. The rapheless valve has a narrow linear axial area and an asymmetric central area. Striae are uniseriate. Areolae are isodiametric and number 35–40 in 10 μm. The central striae have 8–9 areolae in central striae, numbering 35-40 areolae in 10 μm. The external areolae openings are very small.

Original Description

Author: Potapova 2012
Length Range: 9–13 µm
Width Range: 5.0–5.4 µm
Striae in 10 µm: 25–29

Original Description

Original Images

Cite This Page:
Potapova, M. (2012). Psammothidium pennsylvanicum. In Diatoms of the United States. Retrieved April 22, 2018, from

Species: Psammothidium pennsylvanicum

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


Potapova, M. (2012). New species and combinations in monoraphid diatoms (Family Achnanthidiaceae) from North America. Diatom Research 27(1): 29-42. doi:10.1080/0269249X.2011.644636

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)


Autecology Discussion

Psammothidium pennsylvanicum has been found in 15 streams in north central Pennsylvania, including some affected by acid mine drainage. Conductivity in these streams ranged from 6 to 378 μS/cm, and pH from 4.0 to 7.0.