Gyrosigma acuminatum (Kutz.) Rabh.,
Length:94.5

 Width :15

 Transverse striae:18

 Longitudinal striae:24






























Collection 1406a

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Authority information

Gyrosigma acuminatum (Kutz.) Rabh., Sussw.-Diat., p. 47, pl. 5 fig. 5a. 1853 (Patrick and Reimer 1966).

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This image was taken using DIC.




This image is the end of the specimen above.


This image is the central area for the specimen above.


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This taxon has a valve which is moderately sigmoid and lanceolate. It gradually tapers to obtusely rounded ends. The axial area and the raphe are sigmoid as well. The proximal ends of the raphe curve in opposite directions and the central area is longitudinally elliptical. The transverse and longitudinal straie are distinct and the transverse striae are slightly radiate. The longitudinal stria cruve outward to the sides of the central area (Patrick and Reimer 1966).




  • Synonyms
    Frustulia acuminate Kutz., Linnaea, 8:555, pl. 14, fig. 36. 1833 (Patrick and Reimer 1966).
    Navicula acuminataKutz., Bacill., p. 102, pl. 4, fig. 26; pl. 30, fig. 15. 1844 (Patrick and Reimer 1966).


  • Ecology
    This taxon prefers fresh water and is eurytopic and alkalibiont (Patrick and Reimer 1966).

    Size ranges and morphology

  • Length is 60 to 125 micrometers (Patrick and Reimer 1966).
  • Width is 12 to 16 micrometers (Patrick and Reimer 1966).
  • Transverse striae are 16 to 18 in 10 micrometers (Patrick and Reimer 1966).
  • Longitudinal striae are 17 to 20 in 10 micrometers (Patrick and Reimer 1966).