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Cavalier-Smith and von der Heyden, 2007

Pterocystis “ovata”  Cavalier-Smith and Von der Heyden, 2007
  
Diagnosis: Radial spine-scales (3-8 µm) non-striated, lacking transverse ribs, polymorphic, ranging from ovate with a pointed tip, but midrib not extending into a long drawn out cuspidate tip, and dense thickening well away from the base of the scale (about one third along its length), which is much more distinctly rounded than in contorta, to very different strongly cuspidate scales where the tip is much more strongly twisted to one side than in contorta. Tangential plate-scales (3-6 µm) broadly ovate, with central axial ridge, but no radial furrowing, gently indented on one side.
Type locality: Lake sediment, Priest Pot, Cumbria, UK.

Remarks: The name “ovata” has already been used by   Dürrschmidt (1987), which described Acanthocystis ovata, later transferred to the genus Pterocystis by Siemensma (1991).

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