• Category
  • Length Range
    8.5-25 µm
  • Width Range
    2-4 µm
  • Striae in 10 µm
    22-25

Identification

Description

Valves are half-lanceolate or half-elliptical, with the keel of the raphe positioned along the straight margin, rather than along the curved convex margin. The frustule has hantzschioid symmetry. Fibulae number 8-12 in 10 µm. Striae are visible, but are not punctate.

The genus was described from African material and is based on Cymbellonitzschia minima Hustedt, a taxon which has its keel located along the arched portion of the valve, and was described for a species in Africa. Cymbellonitzschia diluviana is present in late glacial sediments and rarely in Recent lake collections in Europe (Jewson and Lowry 1993). It is difficult to imagine the symmetry and raphe organization of the African species and the northern latitude species are part of the same monophyletic group.

In the US, this species is known from large, cool, clean water lakes and is often associated with psammic habitats.

Autecology

Original Description

Cymbellonitzschia diluviana ΗUST., Taf. XLI, Fig. 56-60, gleichzeitig beschrieben in meiner Abhandlung über das Interglazial von Oberohe, sie bildet die wichtigste und eigentümliche Leitform. dieses Interglazials. Im Schaalsee rezent am Westufer des Priestersees, und zwar ziemlich häufig an Ceratophyllum und auf Sand, der in dünner Schicht den schwarzen Faulschlamm überdeckt. In einem der betreffenden Präparate, das zur Kontrolle durchgezählt wurde, konnten unter einem runden Deckglas von 12 mm Durchmesser 12 Individuen festgestellt werden, das ist mindestens derselbe Häufigkeitsgrad, vielfach sogar ein höherer, den die Art in den interglazialen Sedimenten von Oberohe zeigt. Die Form ist recht auffällig, wenn auch klein, und kann kaum übersehen werden. Sie scheint im allgemeinen ausgestorben zu sein, es besteht jedoch die Μöglichkeit, daß sie in einem der weiter östlich gelegenen Seen, die mit dem Schaalsee gleichen geologischen Alters sind, ebenfalls noch rezent vorkommt.

  • Author
    Hust. 1950

Original Images

Cymbellonitzschia diluviana orig illus
Cymbellonitzschia diluviana orig illus 2
Cymbellonitzschia diluviana orig descr

EMAP Assessment

EMAP Distribution

Cymbellonitzschia Diluviana 40 Copy
Map 40

Response Plots

Cymbellonitzschia Diluviana Copy

Cite This Page

Kociolek, P. (2011). Cymbellonitzschia diluviana. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/cymbellonitzschia_diluviana

Responses

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