• Category
  • Length Range
    6-28 µm
  • Width Range
    5.5-8 µm
  • Striae in 10 µm
  • Synonyms
    Martyana martyi (Hérib.) Round 1990
    Fragilaria martyi (Hérib.) Lange-Bert. 1993
  • Reported As
    Fragilaria leptostauron var. martyi (Krammer and Lange-Bertalot 1991, p. 160 fig. 133:28-31)
    Fragilaria mutabilis f. martyi ((Héribaud) Cleve-Euler 1932)
    Fragilaria mutabilis var. intercedens ((Héribaud) Cleve-Euler 1932)



Valve margin variable, from ovoid to elliptic. Valves are coarse, robust, and asymmetric to symmetric to the transapical axes. In other words, valves are typically heteropolar in valve view. A “step” is visible at the headpole of many specimens, but not all. The sternum is usually lanceolate. The striae are coarse and distinctive, and are formed by lineolae. The striae are perpendicular to the apical axis, but become radiate near the ends. A single apical pore field is present at the foot pole. Spines are absent. In girdle view, valves are rectangular and the wide valvocopula is visible. The “step” at the headpole may also be evident.

Due to the absence of spines, S. martyi does not form ribbon-like colonies like some other small fragilarioid taxa. Identification of small specimens is difficult and small valves of S. martyi may be indistinguishable from those of S. ovata and S. pinnata.


Staurosirella martyi is usually found as solitary cells attached to sand grains. Cells may also form zig-zag colonies by means of mucilage pads. In this study, it was found in plankton and epipsammic samples from West Lake Okoboji (Triboji Beach and Gull Point) in Dickinson County, Iowa. Specimens in the Reimer Herbarium included a moist sand site at Miniwaukan State Park, Spirit Lake, Dickinson County, Iowa.

The highest densities of S. martyi recorded by the USGS BioData program have been from creeks and rivers of Nebraska, Wisconsin and Minnesota although there are also abundant records from California, Idaho and Georgia.

This species has been reported to be tolerant of eutrophic waters (Witkowski et al. 1995). In North America, S. martyi has been found in warm (19 -23 ºC), and basic waters (pH 8.3), with conductivities between 312-348 µS/cm (Morales and Manoylov 2005).

Triboji  Rocks 2
Credit: Image by E. Pedraza Garzón
Staurosirella martyi attached to a sand grain
Triboji  Rocks 5
Credit: Image by E. Pedraza Garzón
Zig-Zag colony

Original Description

  • Basionym
    Opephora martyi
  • Author
    Hérib. 1902
  • Length Range
    17 µm
  • Width
    7 µm
  • Striae in 10µm

Original Images

Opephora Martyi Ori Ill
Ophephora  Martyi   Ori Des

EMAP Assessment

EMAP Distribution

Opephora Martyi  H Ribaud 3
Map 3

Response Plots

Opephora Martyi  H Ribaud

Cite This Page

Pedraza Garzon, E. (2014). Staurosirella martyi. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/staurosirella_martyi


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