• Category
  • Length Range
    8.9-18.2 µm
  • Width Range
    3.8-4.6 µm
  • Striae in 10 µm
    28-33

Identification

Description

Valves are linear-elliptic, with ends varying from broadly rounded to slightly protracted. The axial area is narrow and linear. The central area is elliptic, varying from small to medium in size and appearing slightly elevated (confirmed in SEM; Wojtal 2014). The striae are radiate at center valve, becoming parallel and slightly more dense at the apices. The proximal raphe ends are slightly curved in the same direction.

Autecology

Genkalia digitulus favors weakly acidic waters with low mineral content and is most commonly found in lakes (Wojtal et al. 2014). This species is considered to be cosmopolitan and can reach moderately high abundance.

Original Description

105. Navicula digitulus nov. spec. Schalen linear-lanzettlich mit leicht knovexen Seiten und breit und stumpf gerundeten, zuweiten sehr wenig vorgezogenen End, 14-22 μ lang, 3,5-5,5 μ breit. Raphe gerade, fadenförmig. Axialarea sehr eng, Zentralarea klein, aber deutlich, kreisförmig. Transapikalstreifen ziemlich kräftig, im mittleren Teil leicht radial, von den Enden senkrecht zur Mittellinie, etwa 30-32 in 10 μ, in der Mitte etwas entfernter stehend, um 24 in 10 μ, Punktierung äußerst zart. Vereinzelt in einer Grundprobe aus dem Schwarzee. (Abb. 26-30.)

Eine charakteristische kleine Form, die sich von ähnlichen Arten schon durch die ziemlich robusten Schalen unterscheidet, die bei den moisten anderen Navicula-Arten von dieser geringen Größe gewöhnlich nur dünnwandig sind, so daß sie in den Präparaten kaumauffallen. Neuer-dings fan dich dieselbe Art auch in einer Quelle bei Benneckenstein im Harz, so daß eine weitere Verbreitung wahrscheinlich ist. Die Harzer Indi-viduen zeichnen sich durch eine etwas größere Zentralarea aus, stimmen im übrigen mit den Davoser Formen aber völlig überein.

  • Basionym
    Navicula digitulus
  • Author
    Hustedt 1943
  • Length Range
    14-22 µm
  • Width
    3.5-5.5 µm
  • Striae in 10µm
    30-32

Original Images

Navicula Digitulus Orig Illus
Navicula Digitulus Orig Desc

Cite This Page

Tyree, M., Camp, A. (2018). Genkalia digitulus. In Diatoms of North America. Retrieved November 15, 2019, from https://diatoms.org/species/genkalia-digitulus

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Genkalia digitulus 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.