Kützing 1844      Category: Symmetrical biraphid
TYPE SPECIES: Amphipleura pellucida Kützing




Image Credit: Mark Edlund, Sarah Spaulding

CLASS: Bacillariophyceae
  ORDER: Naviculales
    FAMILY: Amphipleuraceae

  1. Median rib present
  2. Medium rib split at the poles, forming 'needle eyes'
  3. Raphe short compared to other naviculoid genera

Amphipleura is distinguished by the narrow, median rib that extends along the long axis of the valve. This rib is formed on the internal face of the valve, a feature observable in SEM. Near the valve apices, the rib forms two branches, or ‘needle eyes’, around the raphe system. The raphe of Amphipleura is short, limited to the area within the “needle eyes”. The valves of Amphipleura are linear or spindle-shaped. The striae are composed of extremely fine areolae (0.25 µm in size), which are difficult to resolve, except under conditions of optimal LM resolution. Because of the fine striae, Amphipleura pellicuda is often used as a test organism for microscope optics. The chloroplast is composed of one central H-shaped plastid with a central pyrenoid.

Amphipleura is common in epipelic habitats of lentic and slowly moving waters, predominately in alkaline pH ranges. Cells grow singly, or may be enclosed in gelatinous tubes.

Cite This Page:
Spaulding, S., and Edlund, M. (2009). Amphipleura. In Diatoms of the United States. Retrieved April 24, 2018, from

Contributor: Sarah Spaulding | Mark Edlund - January 2009
Reviewer: Sam Rushforth - April 2010