Lange-Bertalot and Metzeltin in Werum and Lange-Bertalot 2004 Category: Symmetrical biraphid
BASIONYM: Stauroneis angustilancea Lange-Bertalot and Metzeltin in Werum and Lange-Bertalot 2004
REPORTED AS: Stauroneis (?nov.) spec. Nr. 3 Julma Ölkky (Lange-Bertalot and Metzeltin 1996, Tafel 34, Figs 1-3)
Contributor: Loren Bahls - December 2011
Length Range: 79-125 µm
Width Range: 15-21 µm
Striae in 10 µm: 15-20
Valves are lanceolate with gradually attenuated, weakly protracted, narrow and subrostrate apices. The axial area is narrow and linear, flaring somewhat near the central area. The central area is a rectangular stauros, slightly expanded near the valve margins. Raphe branches are lateral. Proximal raphe ends are weakly deflected to one side and slightly inflated. Terminal raphe fissures are shaped like a question mark and open toward the secondary side. Striae are radiate throughout, more strongly radiate towards the valve apices. Areolae are relatively coarse and number 14-20 in 10 µm.
Basionym: Stauroneis angustilancea
Author: Lange-Bertalot and Metzeltin in Werum and Lange-Bertalot 2004
Length Range: 85-115 µm
Width Range: 14-17 µm
Striae in 10 µm: 17-20
Valvae comparate anguste lanceolatae gradatim attenuatae de media paulatim parum vel modice protractis et obtuse ad parum latius rotundatis, 85-115 µm longae, 14-17 µm latae. Fissurae raphis internae externaeque modice sed distincte laterales sitae in partibus distalibus, in media vix reverse-lateralis sed rectissima in poros centrales comparate parvos leviter unilateraliter declinatos pertinentes. Area axialis fere linearis modice lata ad mediam parum dilatata. Area centralis fasciam (stauros) modice latam formans distincte dilatata usque ad margines (in forma vittae). Striae transapicales conspicue undulantes, radiantes omnino sed magis in partibus distalibus, 17-20/10 µm. Puncta striarum comparate crassa apparentia, 16-18 in 10 µm. A specie similissima, Stauroneis gracilis (associata loco typico) satis differt ad instar et quoad formam fasciae et extrema centralia raphis.
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.
Lange-Bertalot, H. and Metzeltin, D. (1996). Indicators of oligotrophy - 800 taxa representative of three ecologically distinct lake types, Carbonate buffered - Oligodystrophic - Weakly buffered soft water. Lange-Bertalot, H. (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 2. Ecology, Diversity, Taxonomy. Koeltz Scientific Books. Königstein, Germany, 2:390 pp.
Metzeltin, D. and Lange-Bertalot, H. (1998). Tropical diatoms of South America I: About 700 predominantly rarely known or new taxa representative of the neotropical flora. In: Lange-Bertalot, H. (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 5. Diversity-Taxonomy-Geobotany. Koeltz Scientific Books. Königstein, Germany, 5:695 pp.
Werum, M. and Lange-Bertalot, H. (2004). Diatoms in springs, from Central Europe and elsewhere under the influence of hydrogeology and anthropogenic impages. Iconographia Diatomologica 13: 1-417.
Stauroneis angustilancea is widely distributed in fens, ponds, and small lakes across the Northern Rockies. The pH of these waters ranges from 5.5 to 8.1 (mean pH = 6.9) and the specific conductance ranges from 10 to 192 µS/cm (mean SC = 52 µS/cm). This is in contrast to the much higher pH and conductance values preferred by Stauroneis italica. The type habitat for Stauroneis angustilancea is an oligo-dystrophic lake in Finland (Lange-Bertalot & Metzeltin 1996). It has also been reported from a lake in tropical Brazil (Metzeltin & Lange-Bertalot 1998) and from electrolyte-poor waters associated with granite and gneiss formations of the central Alps (Werum & Lange-Bertalot 2004).
Hoodoo Lake, Mineral County, Montana: a typical habitat for Stauroneis angustilancea.
Credit/Source: Google Earth