Gomphosphenia

Lange-Bertalot 1995      Category: Asymmetrical biraphid
TYPE SPECIES: Gomphosphenia lingulatiformis (Lange-Bertalot & Reichardt) Lange-Bertalot

Gomphonema

 

Gyrosigma

Image Credit: Pat Kociolek, Eduardo Morales

CLASS: Bacillariophyceae
  ORDER: Cymbellales
    FAMILY: Rhoicospheniaceae

  1. Valves cuneate
  2. Axial area broad
  3. Proximal raphe with straight ends

Valves cuneate, with straight or undulate sides. Frustules are never bent or flexed. The raphe is straight and filiform, with straight external terminal fissures (both proximal and distal). Internally, the distal raphe fissure terminates in a helictoglossa. Stigmata are absent. Striae composed of open foramina, which may be obscured externally to give the appearance of ghost striae. Apical porefields, septa and pseudosepta are all absent in Gomphosphenia.

Gomphosphenia contains a small number of species and was separated fairly recently from Gomphonema (Lange-Bertalot 1995). Two species, G. grovei and G. lingulataeforme are widely distributed in benthic habitats of North America. Wallace (1960) documented variation in Gomphonema brasiliense, a taxon now considered within Gomphosphenia.

Cite This Page:
Spaulding, S. (2011). Gomphosphenia. In Diatoms of the United States. Retrieved September 02, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/gomphosphenia

Contributor: Sarah Spaulding - January 2011