• Category
  • Length Range
    4.3-6.3 µm
  • Width Range
    4.1-5.6 µm
  • Striae in 10 µm
    18-21
  • Synonyms
    Melosira cataractarum Hust. 1937
    Aulacoseira cataractarum (Hust.) Simonsen 1979
    Pseudostaurosira cataractum (Hust.) Wetzel, Morales and Ector 2013

Identification

Description

Valves are circular to slightly elliptic. The valve face is flat. Striae are radiate and are present throughout the valve, although the striae shorten toward the valve apices creating an elliptic axial area. This asymmetry, however, is not present in all valves as some valves may appear to be circular. A wider vimen and the small cell size cause the striae to not be continuous from the valve face to mantle. Costae are wider than the striae across the valve.

Frustules are rectangular in girdle view and have a box-like appearance where striae and/or spines can be seen. The transition between the valve face and mantle is at nearly a 90-degree angle. Valves are joined together by interlocking spines, mostly found on virgae (costae). Due to the small size of the diatom, the spine position is not fixed and can sometimes be found along the striae. Spathulate spines are located on the costae on the valve margin. The girdle bands are segmented, a feature visible in SEM.

Apical porefields and rimoportula are absent.

Size ranges for this taxon have been expanded from Hustedt's original dimension. This population fits within the more recently reported ranges (Wetzel et al. 2013, Grana et al. 2015).

Autecology

Nanofrustulum cataractarum was recovered from the wetland area of Gull Lake, a small lake in the eastern Sierra Nevada, California. This species has also been reported from springs, splash zones in waterfalls and rivers, wet but exposed environments and in some occasions from warm springs.

Original Description

Melosira cataractarum nov. spec. Zellen zylindrisch , kurze Faden bildend. Schalenflache fast volling eben, daher zwischen je zwei Zellen nu rein schwach entwickelter Pseudosulcus. Schalenmatels mit sehr flachem Sulcus. Durchmesser 4,5-6 µ, Hohe des Schalenmantels 2-3 µ. Zellwand dunn, innere Mantellinien gerade. Struktur verhaltnismabig grob, auf der Mantelflache zart punktierte, steile oder wenig geneigte Streifen, etwa 18 in 10 µ, auf der Schalenflache kurze Randstreifen von unregelmabiger Lange, die ein griberes Mittelfeld freilassen und daher eine auffallande Ahnlichkeit mit Cyclotellen hervorrufen. Schalenrand mit zarten Dornen besetzt, die bei benachbarten Zellen alternierend ineinander greifen. Taf. IX. Fig. 6, 7.

Vorkommen und Verbreitung: Bisher nur in einer Probe aus West Java beobachtet: ziemlich haufig an tief schattigen Moosen im Sritzwassar des Wasserfalles Tjurug Tjibeureum, pH=8,1.

Von kleinen Individuen der habituell ahnlichen Mel. Ikapoensis besonders durch die Struktur der Diskusflache zu unterscheiden. Bei M. ikapoensis greifen die Streifen der Mantelflache nur wenig auf die Diskusflache uber, so dab sehr grobes Mittelfeld belibt, das (wei bei Melosira distans) durchwegdeutlich poroidist.

  • Basionym
    Melosira cataractarum
  • Author
    Hust. 1937
  • Length Range
    4.5-6 µm
  • Width
    2-3 µm
  • Striae in 10µm
    18

Original Images

Melosira cataractum orig illus
Melosira cataractum orig desc

Citations & Links

Citations

Links

Cite This Page

Congote, L. (2022). Nanofrustulum cataractarum. In Diatoms of North America. Retrieved February 27, 2024, from https://diatoms.org/species/nanofrustulum-cataractarum

Responses

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