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Gomphonema

Gomphonema are heteropolar diatoms, asymmetrical over the transapical axis.  One pole is distinctly wider than the other, giving it the appearance of a club.  In girdle view, the cells appear wedge shaped.  Unlike its sister genus Gomphoneis, the striae of Gomphonema do not have lines along the apical axis.

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***The species of Gomphonema pictured below have not all been identified to a species level, because other identification resources do not have species that match up well with them.  However, photos have been sorted into tentative groups and described with important identifying characteristics.

Footpole

Headpole

G. turgidium var. x

  • Pictured specimens belong to an unknown variation of the species G. turgidium.  Headpoles become narrower near the tip, more so than typical G. turgidium.

  • Unfortunately, detailed species information is only available for the main species of G. turgidium, not the variant pictured here. 

  • The species is easily identified by its dramatic differences between the width of the headpole and footpole, and the blockiness of the headpole.

For more information on G. turgidium, visit diatoms.org here.

Gomphonema sp. 1

  • Specimens are 32-34 µm in length.

  • Striae are radiate at the center, and parallel at the poles.  Striae on opposite sides are offset.

  • Wide raphe canal on the footpole.

  • Headpole stays almost as wide as the valve middle, and has a rounded end.

Gomphonema sp. 2

  • Striae are slightly radiate at the center, becoming more parallel towards the poles.  Striae are offset across the raphe.

  • Both the headpole and footpole appear pinched just before the tips.

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Gomphonema sp. 3

  • Cell larger than other species.

  • Striae slightly radiate for the duration of the valve face.

  • Footpole is longer than the headpole.

  • Valve is diamond-shaped, with pointed ends.

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