Stauroneis absaroka
Bahls 2010 Category: Symmetrical biraphid
BASIONYM: Stauroneis absaroka Bahls 2010
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Loren Bahls - December 2011
Length Range: 43-75 µm
Width Range: 10.1-14.7 µm
Striae in 10 µm: 17-19
Description
Valves are lanceolate with subrostrate to subcapitate apices. The axial area is broad, often with an irregular border formed by the ends of striae, widening gradually towards the central area. The central area is a very broad stauros, widening markedly toward the valve margins. Curved striae border the stauros. Shortened striae have not been observed in the central area. The raphe branches are moderately lateral. Proximal raphe ends are strongly curved and tipped with distinctly inflated, drop-like central pores. Striae are radiate throughout and curved about the central area. Striae puncta are distinct and number 22-26 in 10 µm.
Original Description
Basionym: Stauroneis absaroka
Author: Bahls 2010
Length Range: 43-75 µm
Width Range: 10.1-14.7 µm
Striae in 10 µm: 17-19
Original Description
Valves lanceolate with subrostrate to subcapitate ends. Length 43-75 µm, width 10.1-14.7 µm. Axial area wide, often with an irregular border, expanding gradually toward the central area. Central area a very broad butterfly-shaped fascia, widening markedly toward the valve margins. Shortened striae not observed in the central area. Raphe fissures moderately lateral, proximal endings strongly curved and tipped with distinctly inflated, drop-like central pores. Striae curved and radiate throughout, 17-19 in 10 µm. Striae puncta distinct, 22-26 in 10 µm. For measurements, n = 14 valves.
Original Images
Cite This Page:
Bahls, L. (2011). Stauroneis absaroka. In Diatoms of the United States. Retrieved May 18, 2013, from http://westerndiatoms.colorado.edu/taxa/species/stauroneis_absaroka
Species: Stauroneis absaroka
Contributor: Loren Bahls
Reviewer: Sam Rushforth
Image Credit: Loren Bahls
- Axial area broad, often with irregular ends of striae
- Broad stauros with curved margins
- Proximal raphe ends curved, tipped with drop-like ends
- Striae curved near the central area
Stauroneis absaroka has lanceolate valves with subrostrate to subcapitate apices. The axial area is broad and often has irregular borders formed by the striae. Proximal raphe ends are distinctly curved and tipped with drop-like ends. Striae are curved on the margins of the broad stauros.
Compare
Stauroneis absaroka may be distinguished from S. amphicephala by its wider axial and central areas, more strongly deflected proximal raphe ends, and drop-like central pores. Stauroneis acidoclinata has more linear valves, narrower axial and central areas, less strongly deflected proximal raphe ends, and smaller central pores. Stauroneis ancepsfallax has capitate apices, a narrow axial area, and nearly straight proximal raphe ends. Stauroneis vandevijveri has a narrow axial area and straight proximal raphe ends with unexpanded central pores.
Stauroneis acidoclinata
Stauroneis amphicephala
Stauroneis ancepsfallax
Stauroneis vandevijveri
Citations
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)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID:
Autecology Discussion
Stauroneis absaroka has been recorded from five lakes and ponds in southwest Montana. The pH of these waters ranges from 6.1 to 7.8 and specific conductance ranges from 21 to 41 µS/cm. This taxon is uncommon and only a minor component of the diatom assemblage at each location where it was found.
Images
Bloody Dick Pond #3, Beaverhead County, Montana: home of Stauroneis absaroka.
Credit/Source: Loren Bahls