Stauroneis rex

Bahls 2010      Category: Symmetrical biraphid

Stauroneis reichardtii


Stauroneis sacajaweae

LM scalebar = 10 µm = 20 pixels.


Contributor: Loren Bahls - November 2011
Length Range: 215-386 µm
Width Range: 38-60 µm
Striae in 10 µm: 12-14


Valves are lanceolate and very large with blunt, broadly rounded apices. The axial area is moderately broad and linear. The central area is a rectangular stauros, often narrowing somewhat toward the valve margins. Short striae may be present in the central area. External raphe fissures are lateral. Proximal raphe ends are straight and somewhat inflated. Striae are radiate throughout. Areolae are coarse and number 11-14 in 10 µm.

Original Description

Author: Bahls 2010
Length Range: 215-386 µm
Width Range: 38-60 µm
Striae in 10 µm: 12-14

Original Description

Valves are very large and broadly lanceolate with blunt, broadly rounded ends. Length 215-386 µm, width 38-60 µm. Length to width ratio: 5.6-6.5. Axial area moderately broad and linear. Central area a rectangular fascia, narrowing somewhat toward the valve margins. Shortened striae may be present. External raphe fissures lateral, proximal endings somewhat inflated and straight. Terminal raphe fissures hooked, opening toward the secondary side. Striae radiate throughout, 12-14 in 10 µm. Striae puncta coarse, 11-14 in 10 µm. For measurements, n = 68 valves.

Original Images

Cite This Page:
Bahls, L. (2011). Stauroneis rex. In Diatoms of the United States. Retrieved March 19, 2018, from

Species: Stauroneis rex

Contributor: Loren Bahls

Reviewer: Mark Edlund


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.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Stauroneis rex CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Stauroneis rex is widely distributed in ponds and small lakes in the Northern Rockies. These waters tend to be alkaline (mean pH = 7.8) with moderate concentrations of electrolytes (mean specific conductance = 194 µS/cm). In contrast, Stauroneis phoenicenteron prefers circumneutral waters (mean pH = 7.1) with low concentrations of electrolytes (mean specific conductance = 34 µS/cm).


Handkerchief Lake, Flathead County, Montana: type locality of Stauroneis rex.

Credit/Source: Loren Bahls