Pfitzer 1871      Category: Symmetrical biraphid
TYPE SPECIES: Anomoeoneis sphaerophora Pfitzer




Image Credit: Ditmar Metzeltin

CLASS: Bacillariophyceae
  ORDER: Cymbellales?
    FAMILY: Anomoeoneidaceae

  1. Striae distinctly punctate and irregular
  2. Central area extends to valve margins
  3. Distal raphe ends deflected and usually distinct

Anomoeoneis valves are lanceolate to elliptical-lanceolate in outline, with broadly rounded to capitate apices. The central area may be symmetrical or asymmetrical, extending unilaterally to valve margins. The distal raphe ends are deflected and usually distinct. The irregular striae and hyaline areas on both sides of the axial area distinguish Anomoeneis from Brachysira and Navicula. The chloroplast is a single multi-lobed plastid with a large spherical pyrenoid.

Anomoeoneis species grow in epipelic habitats of high conductance and brackish water, including estuaries. It is especially common in saline inland waters of the mid-western United States and western Canada.

Cite This Page:
Spaulding, S., Edlund, M., and Metzeltin, D. (2009). Anomoeoneis. In Diatoms of the United States. Retrieved April 23, 2018, from

Contributor: Sarah Spaulding | Mark Edlund | Ditmar Metzeltin - January 2009