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Diatoms of the United States is now known as Diatoms of North America.
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Krammer 1997      Category: Asymmetrical biraphid
TYPE SPECIES: Encyonopsis cesatii Krammer




Image Credit: Loren Bahls

CLASS: Bacillariophyceae
  ORDER: Cymbellales
    FAMILY: Cymbellaceae

  1. Valves naviculoid, slight apical asymmetry
  2. Areolae round or transapically elongate
  3. Striae radiate or parallel at the apices
  4. Proximal raphe ends deflected dorsally
  5. Distal raphe fissures deflected ventrally

Valves are naviculoid and slightly dorsiventral, symmetric to the transapical axis and asymmetric to the apical axis. The raphe is centrally located. Areolae in the striae are round or oblong and oriented with their long axes parallel to the transapical axis. Transapical striae are radiate near the valve center and radiate or parallel near the apices. Proximal raphe ends are deflected toward the dorsal margin. Distal raphe fissures are deflected ventrally. Stigmata and apical pore fields are absent.

Encyonopsis is distinguished from Kurtkrammeria by the orientation of the striae at the valve apices, by the shape and orientation of the areolae, and by other features observed in SEM. In Encyonopsis species, areolae are round or elongate in a transapical direction. In Kurtkrammeria, areolae are slit-like or crescent shaped with the long axis oriented apically. In Encyonopsis, the terminal striae are radiate or parallel; in Kurtkrammeria, terminal striae are convergent. Stigmata and apical pore fields may be present in Kurtkrammeria, but they are absent in Encyonopsis.

Cite This Page:
Bahls, L. (2015). Encyonopsis. In Diatoms of the United States. Retrieved May 23, 2018, from

Contributor: Loren Bahls - December 2015
Reviewer: Sarah Spaulding - December 2015


November 8th, 2015 - Change in circumscription

The concept of the genus Encyonopsis was changed to become more narrow as of this date. The genus Kurtkrammeria was recognized and established as a new genus. Formerly, Encyonopsis included the broader definition.