Psammothidium incognitum

Taxon ID: 320
Author: Krasske 1939   
Basionym: Achnanthes incognita
Synonym: Navicula dulcis, Achnanthes stauroneioides f. striata

 

Images

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LM image scalebar = 10 µm = pixels not measured     

 

Observations

Observations: Bart Van de Vijver
Length: 13-18µm
Width: 4-5,5µm
Striae: Transapical striae 30 in 10µm in the median part; 40 striae in 10µm towards the ends

Description:

Valves elliptical to linear-lanceolate, the median part with parallel borders, cuneate endings (L 13-18µm, W 4-5,5µm). Transapical striae 30 in 10µm in the median part, slightly radiate, 40 striae in 10µm towards the ends. RV: raphe filiform with internally central terminals curved in opposite directions, narrow axial area. Central area very wide, extending towards both sides. ARV: longitudinal area very narrow with rounded central part. The middle striae radial but larger and more spaced than the other striae.

Morphology: Monoraphid
Distribution:

Autecology:

 

Notes:

Mostly found on relatively dry, acid soils without much vegetation cover. In mosses and open waterbodies, no observations were made although on South Georgia, it seems quite common on wet, submerged mosses (Van de Vijver & Beyens 1997a).Originally described from southern Chile (Krasske 1939), Kerguelen (Le Cohu & Maillard 1983) South Georgia (Van de Vijver & Beyens 1996, 1997a), South Shetland Islands (Björck et al. 1991), South Orkney Islands (e.g. Jones et al. 1993).A. stauroneioides f. striata Maillard should be considered as a younger synonym of Psammothidium incognitum. Although Lange-Bertalot & Krammer (1989) considered P. stauroneioides (Manguin) Bukht. & Round also to be a regional variation of P. incognitum due to similarities of the raphid valve, the latter should be kept as a separate species based on the structure of the araphid valve. Both Le Cohu & Maillard (1983) and Oppenheim (1994) gave sufficient arguments for this theory.

 

 

Other sites with Psammothidium incognitum

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

Original Type Description

Author: Krasske 1939
Length:
Width:
Striae:

Original Description:

 

New combination

Author: Van de Vijver

 

Citations

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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