Distrionella
Williams 1990 Category: Araphid
TYPE SPECIES: Distronella asterionelloides Williams
Image Credit: Eduardo Morales
CLASS: Fragilariophyceae
ORDER: Fragilariales
FAMILY: Fragilariaceae
- Valves elongated, with capitate ends
- Striae unevenly spaced
- Rimoportula single, often central within a stria near one pole
Frustules of Distrionella are elongated with capitate ends. Valves may be slightly asymmetrical to the transapical axis. Striae are unevenly spaced and become scattered and more irregular at the valve ends. Transapical ribs often evident. A central sternum is absent. Porefields, composed of simple porelli, are present at both valve ends. One rimoportula is present, and is usually positioned centrally within a stria near one pole.
Distrionella is distinguished from Diatoma by its more lightly silicified valves and weaker transapical ribs. It is considered to be closely related to Diatoma and Asterionella. Distrionella incognita is common in lakes and rivers of Montana and Idaho.
Cite This Page:
Spaulding, S., and Edlund, M. (2009). Distrionella. In Diatoms of the United States. Retrieved May 24, 2013, from http://westerndiatoms.colorado.edu/taxa/genus/Distrionella
Contributor: Sarah Spaulding | Mark Edlund - January 2009
Reviewer: Sam Rushforth
Citations
Morales, E.A., Bahls, L.L. and Cody, W.R. (2005). Morphological studies of Distrionella incognita (Reichardt) Williams (Bacillariophyceae) from North America with comments on the taxonomy of Distrionella Williams. Diatom Research 20: 115–135.
Williams, D.M. (1990). Cladistic analysis of some freshwater araphid diatoms (Bacillariophyta) with particular reference to Diatoma and Meridion. Plant Systematics and Evolution 171: 1615-6110.
Williams, D.M. (1990). Distrionella D.M. Williams, nov. gen., a new araphid diatom (Bacillariophyta) genus closely related to Diatoma Bory. Archiv für Protistenkunde 138: 171-177.