• Category
  • Length Range
    79-125 µm
  • Width Range
    15-21 µm
  • Striae in 10 µm
    15-20
  • Reported As
    Stauroneis (?nov.) spec. Nr. 3 Julma Ölkky (Lange-Bertalot and Metzeltin 1996, Tafel 34, Figs 1-3)

Identification

Description

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.

Autecology

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
Credit: Google Earth
Hoodoo Lake, Mineral County, Montana: a typical habitat for Stauroneis angustilancea.

Original Description

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.

  • Author
    Lange-Bert. and Metzeltin in Werum and Lange-Bert. 2004
  • Length Range
    85-115 µm
  • Width
    14-17 µm
  • Striae in 10µm
    17-20

Original Images

Sangustilanc Origimag
Sangustilanc Origdesc3

Cite This Page

Bahls, L. (2011). Stauroneis angustilancea. In Diatoms of North America. Retrieved July 20, 2018, from https://diatoms.org/species/stauroneis_angustilancea

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Stauroneis angustilancea from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.