Stauroneis fluminopsis

Van de Vijver and Lange-Bert. 2004      Category: Symmetrical biraphid

Stauroneis finlandia


Stauroneis gracilis

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - December 2011
Length Range: 76-101 µm
Width Range: 17-22 µm
Striae in 10 µm: 15-18


Valves are broadly linear-lanceolate with bluntly rounded subrostrate apices. The axial area is linear, two to three times wider than the raphe, and only slightly wider near the central area. The central area is a narrow, almost rectangular stauros, expanding slightly towards the valve margins. Short striae are sometimes present in the stauros at the valve margins. The raphe is lateral, becoming filiform at the ends. Terminal raphe fissures are hooked. Proximal raphe ends are nearly straight and slightly inflated. Striae are wavy and radiate throughout. Areolae are coarse and number 14-17 in 10 µm.

Original Description

Author: Van de Vijver and Lange-Bert. 2004
Length Range: 75-115 µm
Width Range: 17.5-22 µm
Striae in 10 µm: 16-18

Original Description

Valves linear-lanceolate with more or less distinct (but not abruptly) protracted subrostrate to cuneately rostrate and bluntly rounded ends. Length 74-115 µm, breadth 17.5-22 µm. Pseudosepta absent. Raphe moderately lateral with almost straight central endings as far as the central pores are barely deflected towards the side. Axial area almost large. Central area forming a moderately large fascia, only slightly widened towards the valve margins. Very short striae are sometimes present at the face/mantle junction. Striae radiate throughout the entire valve, 16-18 in 10 µm. The puncta of the striae are regularly spaced, around 18 in 10 µm.

Original Images

Cite This Page:
Bahls, L. (2011). Stauroneis fluminopsis. In Diatoms of the United States. Retrieved April 20, 2018, from

Species: Stauroneis fluminopsis

Contributor: Loren Bahls

Reviewer: Marina Potapova


Bahls, L. (2010). Stauroneis in the Northern Rockies: 50 species of Stauroneis sensu stricto from western Montana, northern Idaho, northeastern Washington and southwestern Alberta, including 16 species described as new. Northwest Diatoms, Volume 4. The Montana Diatom Collection, Helena, 172 pp.

Van de Vijver, B., Beyens, L. and Lange-Bertalot, H. (2004). The genus Stauroneis in Arctic and Antarctic Regions. Bibliotheca Diatomologica 50, 312 pp.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

North American Diatom Ecological Database (NADED)


Autecology Discussion

Stauroneis fluminopsis was found in six lakes and wetlands in the Northern Rockies. The pH of these waters ranges from 6.0 to 8.6 and specific conductance ranges from 40 to 250 µS/cm. Van de Vijver et al. (2004) described this species from the Antarctic, where it was found in pools and small rivers with a pH of 6.0-7.5 and a specific conductance of 50-200 µS/cm.


Holland Lake, Missoula County, Montana: home of Stauroneis fluminopsis.

Credit/Source: Loren Bahls