Staurosirella pinnata (Ehrenb.) Williams and Round, comb. nov. 1987
Length: 9

 Width: 4

Striae:10






























Collection 1226

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Williams and Round 1987


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Originally, the pictured specimen was identified as Fragilaria pinnata in Patrick and Reimer 1966 , and the following information refers to this taxon.
This species is attached by the valve faces into band-like colonies (Stoermer and Yang 1969).
  • Basionym (Williams and Round 1987)
    Fragilaria pinnata Ehrenberg 1843b: 415, pl. 3 (6), fig. 8 a-e.
  • Synonyms (Patrick and Reimer 1966)
    Fragilaria elliptica Schum. 1867

  • Ecology
    Fragilaria pinnata is widely distributed in freshwater systems (Patrick and Reimer 1966). In the Great Lakes, specimens of this species were scattered in collections from nearshore areas from Lake Michigan. Occasionally this species was found in low numbers in offshore collections, especially during the fall months (Stoermer and Yang 1969).

    Size ranges and morphology

  • For Fragilaria pinnata :
  • Length is 3-35 micrometers (Patrick and Reimer 1966).
  • Breadth is 2-6 micrometers (Patrick and Reimer 1966).
  • Striae range is 7-12 per 10 micrometers (Patrick and Reimer 1966).
  • In Lake Michigan, the length of Fragilaria pinnata ranges from 5-30 micrometers. The breadth ranges from 2-6 micrometers and the striae numbers range from 8-11 striae in 10 micrometers (Stoermer and Yang 1969).