Pinnularia rhombarea var. serrata

Taxon ID: 309
Author: Van de Vijver & Beyens    



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LM image scalebar = 10 µm = pixels not measured     



Observations: Bart Van de Vijver
Length: 48-83µm
Width: 9,3-12,7µm
Striae: 11-13 striae in 10µm


Valves linear with parallel to weakly convex margins and broadly rounded, rostrate apices (L 48-83µm, W 9,3-12,7µm, 11-13 striae in 10µm). Axial area narrow, linear. Central area rhomboid, clearly asymmetrical, with a broad fascia. Raphe weakly lateral with large teardrop-shaped central pores, laterally deflected. Terminal fissures large, ?- to sickle-shaped, good resolvable in LM. Transapical striae radiate in the middle, convergent towards the apices. A single stria is sometimes present in the middle of the valve. No longitudinal lines present.

Morphology: Naviculoid




Pointe Basse (Grande Coulée), Ile de la Possession, Crozet Archipelago, Sample BA010 (coll. date 03/01/1998).Frequently found (low abundances) in acid, relatively dry (40-60%) soil samples with higher specific conductance values (>300µS/cm). Prefers also electrolyte enriched lakes, close to the sea. Rare in mosses.So far only found on Ile de la Possession.This new variety might be included within the var. rhombarea but based on several features, we decided to separate these two varieties. The raphe is clearly visible in LM, a characteristic not shared by the var. rhombarea. Together with the smaller width and the higher number of striae, the creation of the new variety serrata can be justified.



Other sites with Pinnularia rhombarea var. serrata

  • Ile de la Possession (moist habitats), Crozet Archipelago

Original Type Description

Author: Van de Vijver & Beyens
Length: 48-83µm
Width: 9,3-12,7µm
Striae: 11-13 striae in 10µm

Original Description:

Width smaller than in the nominate variety. The terminal fissures are quite large and therefore good resolvable in LM. Number of striae in 10µm larger than the nominate variety.


New combination




Index Nominum Algarum (INA):

  • Original
  • If an INA link is available, it will be shown above
  • The INA is a bibliographic reference "card file" for algal taxonomy, containing nearly 200,000 names of algae (in the broad sense).

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