Ralfs 1843 Category: Araphid
TYPE SPECIES: Tetracyclus lacustris Ralfs
Frustules of Tetracyclus are heavily silicified. The valves are elliptical to elongate, and often capitate. The valve margins may be expanded centrally. The valve face is flat, while the valve mantle is relatively high. Striae are uniseriate and continue over the costae. Valves may have up to two rimoportulae, positioned near the valve center. Cells form zig-zag colonies joined by mucilage pads.
Tetracyclus is considered a close relative of Tabellaria. Tetracyclus is common in the fossil lacustrine deposits of western North America. In present day sites, it occurs mostly in high latitude and high altitude oliotrophic lakes.
Cite This Page:
Spaulding, S., and Edlund, M. (2008). Tetracyclus. In Diatoms of the United States. Retrieved June 19, 2013, from http://westerndiatoms.colorado.edu/taxa/genus/Tetracyclus