• Category
  • Diameter
    10.8-15.7 µm
  • Striae in 10 µm
    19-20
  • Reported As
    Puncticulata praetermissa (Tanaka 2007, p. 43, plates 56-59)

Identification

Description

Cells are cylindrical with shallow mantles. The valve face is nearly flat, with a marginal ring of short striae and a central area of many scattered, uniform-sized and evenly-spaced areolae. The areolae may be arranged in a weakly radiate pattern in some specimens. The short marginal striae are slightly unequal in length and composed of very fine areolae. Every fourth or fifth costa is thickened. The costae appear in LM number about 5 in 10 µm.

Håkansson (2002), Houk et al. (2010), Krammer and Lange-Bertalot (1991) and Tanaka (2007) published SEM images and descriptions of P. praetermissa from regions outside of North American. External views show a domed central area, with external openings of areolae and central fultoportulae surrounded by a slight depression. Surrounding the central area are 1 to 5 rimoportula. The marginal area consists of multiseriate striae that continue onto the mantle. Areolae in the striae are much finer than those in the central area. A ring of marginal fultoportulae occurs at the junction of the valve face and mantle.

Internally, striae are expressed as short oblong alveoli separated by costae. The costae are sometimes divided and every fourth or fifth costa is thickened and bears a marginal fultoportula. The fultoportula which consist of a short tube with two lateral satellite pores. One to 5 rimoportulae are located between the central area and the marginal alveoli. The central area is concentrically undulate, with many areolae and central fultoportulae scattered or arranged in radial rows. Each central areola is covered with a domed cribrum. Central fultoportulae consist of a short tube surrounded by three satellite pores.

Note that stria density is variously reported in the literature as 15-18 in 10 µm (Houk et al. 2010), 13-15 in 10 µm (Håkansson 2002), and 13-19 in 10 µm (Krammer & Lange-Bertalot 1991). The stria density of Montana specimens ranges from 19 to 20 in 10 µm. This variability may be due, in part, to different measurement techniques employed by various investigators.

Autecology

Cyclotella praetermissa may occur as solitary cells or in short chains of 2-8 cells enclosed in a mucous sheath (Houk et al. 2010). The species was described from material collected at Blelham Tarn in the English Lake District (Lund 1951). Houk et al. (2010) report it from two oligotrophic/mesotrophic lakes in Germany, where it occurs in the plankton and the littoral zone. Tanaka (2007) reports C. praetermissa from several mesotrophic and eutrophic lakes and ponds in Japan. Specimens shown here are from Bowman Lake (photo below) and Kintla Lake in Glacier National Park, Montana. It has also been reported from Waterton Lake in the Waterton/Glacier International Peace Park. In these waters pH ranges from 8.25 to 8.53 and specific conductance from 122 to 149 µS/cm.

Bowman  Lake
Credit: Loren Bahls
Bowman Lake, Glacier National Park, Montana: home of Cyclotella praetermissa.

Original Description

  • Basionym
    Cyclotella praetermissa
  • Author
    Lund 1951

Citations & Links

Citations

Links

Updates

Aug 15, 2018 - Transfer from Cyclotella praetermissa

Transferred on this website from C. praetermissa to L. praetermissa, following Nakov et al. (2015). - S. Spaulding

Cite This Page

Bahls, L. (2013). Lindavia praetermissa. In Diatoms of North America. Retrieved August 15, 2018, from https://diatoms.org/species/lindavia_praetermissa

Responses

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