Johansen and Sray 1998      Category: Symmetrical biraphid
TYPE SPECIES: Microcostatus krasskei (Hustedt) Johansen and Sray




Image Credit: Rex Lowe

CLASS: Bacillariophyceae
  ORDER: Naviculales

  1. Central sternum prominent
  2. Axial depressions present
  3. Axial depressions contain small costae

Frustules of Microcostatus are small in size. The axial area includes lyre-shaped depressions on both sides of the prominent sternum. The depressions contain small costae (microcostae) in a depression near the axial area. Striae not visible with the light microscope. SEM reveals striae are present and comprised of single rows of areolae. In living cells two plastids are present, pressed to the cingulum. The genus differs from Fallacia by the absense of a conopeum.

The genus includes species that belong to the former section Naviculae minusculae. This group The genus contains Microcostatus krasskei (Hustedt) Johansen and Sray, M. naumanii (Hustedt) Lange-Bertalot and M. maceria (Schim.) Lange-Bertalot, Kusber and Metzeltin, among others. Microcostatus is typically found in aerophilous habitats, such as wet walls or soils.

Cite This Page:
Spaulding, S., and Edlund, M. (2008). Microcostatus. In Diatoms of the United States. Retrieved April 22, 2018, from http://westerndiatoms.colorado.edu/taxa/genus/Microcostatus

Contributor: Sarah Spaulding | Mark Edlund - December 2008
Reviewer: Sam Rushforth - June 2010