• Category
  • Length Range
    14.6-26.6 µm
  • Width Range
    4.1-5.6 µm
  • Striae in 10 µm
    16-20
  • Synonyms
    Fragilaria capucina var. capitellata Krammer and Lange-Bert. 1991
    Fragilaria capitellata (Grunow in Van Heurck) Peterson
    non Fragilaria capitellata Laudy 1910

Identification

Description

Valves are wide and linear, with highly constricted, capitate ends. The axial area is narrow and widens slightly near the central area. The central area is unilaterally expanded to the valve margin. Stria density is uniform across the valve. A single rimoportula is present at one end of the valve. A porefield is present at each apex, positioned on the valve mantle and composed of several transapically aligned rows of pores extending slightly onto the valve face. In valve view, frustules are rectangular.

Spines were not observed in SEM, nor were long, band shaped colonies.

The name, F. recapitellata is a new name for Fragilaria capitellata (Grunow in Van Heurck) Petersen 1946 (non Lauby 1910). Note that the taxon illustrated here conforms more to the taxon illustrated in Metzeltin et al. (2009) than in the original description of Synedra capitellata Grunow in Van Heurck 1881.

Autecology

In North America, Fragilaria recapitellata has been documented in the Great Lakes (Stoermer et al, 1999) and in rivers in the Central Sierra Nevada (USGS NAQWA Survey).

Original Description

  • Basionym
    Synedra capitellata
  • Author
    Grunow in Van Heurck 1881
  • Striae in 10µm
    15-18

Original Images

Synedra Capitellata Original Image 2
Synedra Capitellata Original Image

EMAP Assessment

EMAP Distribution

Fragilaria Capucina Var  Capitellata   Grunow   Lange  Bertalot 3
Map 3

Response Plots

Fragilaria Capucina Var  Capitellata

Updates

Jul 22, 2018 - Extension of Size Range

Prior to this date, length for this taxon was documented as 19.1-29.1 µm. This range was expanded to include smaller specimens found in a separate population by the contributor. The smallest image was taken from this latter population. - I. Bishop

Cite This Page

Bishop, I, and Spaulding, S. (2014). Fragilaria recapitellata. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/fragilaria_capucina_var._capitellata

Responses

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