• Category
  • Length Range
    15.5-56 µm
  • Width Range
    10-25 µm
  • Striae in 10 µm
  • Reported As
    Surirella ovata (Hustedt 1930)



The heteropolar valves are 15.5-56 µm long by 10-25 µm wide. The headpole is broadly rounded and the footpole is cuneately rounded. In valves shorter that 30 µm, the footpole becomes broadly rounded as well, however it remains slightly narrower than the head pole. The valves are slightly concentrically undulate. The costae extend from the margins to the apical axis with 18-23 in 10 µm. Every third or fourth costa on the valve face is raised above the others and corresponds to the fibula on the valve interior. The fibulae are marginal and have a density of 5-6 in 10 µm.

Krammer & Lange-Bertalot (1987) note that there are 3-4 portulae on the mantle face between the fibulae.


Original Description

Surirella brebissonii nov.spec. (Figs 1(ov2), 4,4,9,21-33)

Surirella ovata var. marina Brebisson 1867 in Rabh. Alg. Eur., no. 2011 Surirella ovata sensu Hustedt 1930, figs 863,864 valvae ovat-ellipticae vel late ovatae, a latere primario cuneata, a latere secundario rotundata, 16-70 µm longae, 16-30µm latae. Costae marginales 35-60/100 µm, striae transapicales (16)17-19/10 µm. Apical axis of the frustules heteropolar, girdle view slightly cuneiform. Larger valves linear-ovate, the smaller ovate and the smallest broadly elliptical to nearly round. In large forms on end is cuneately rounded, the other broadly rounded; in smaller forms both ends are almost equally rounded. Length 16-70µm, breadth 16-30 µm. Inner wall of the raphe canal with 3-4 portulae between two adjacent fibulae (in one interfibular space). Valve face concentrically undulate, the middle of the valve having a shape like a saddle roof. Pseudoinfundibula arranged in a marginal zone, the number/100 µm conforming to the number of fibulae. Between the pseudoinfundibula and the saddle roof a depression runs parallel to the outline of the valve. Axial area narrow, linear or narrower to broader lanceolate; all other parts of the valve are covered with small waves (in LM 'striae'), (16)17-19/10 µm, each of them with 2-4 rows areolae. Holotypus: Coll. Krammer P 1107A (Figs 21-26) Type Locality: Falaise, (Material of Brebisson) Distribution: Cosmopolitan, common in fresh water of moderate to high electrolyte content; frequently abundant also in brackish waters by sea coasts.

  • Author
    Krammer and Lange-Bert. 1987
  • Length Range
    16-70 µm
  • Width
    16-30 µm
  • Striae in 10µm

Original Images

Surirella brebissonii orig illus
Surirella brebissonii orig descr

EMAP Assessment

EMAP Distribution

Surirella Brebissonii 40 Copy
Map 40

Response Plots

Surirella Brebissonii Copy

Cite This Page

English, J, and Potapova, M. (2011). Surirella brebissonii. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/surirella_brebissonii


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