Amphora minutissima

W.Sm. 1953      Category: Asymmetrical biraphid

Amphora copulata


Amphora ovalis

LM scalebar = 10 µm = 80 pixels.


Contributor: Joshua Stepanek - February 2011
Length Range: 13-20 µm
Width Range: 3.5-5 µm
Striae in 10 µm: 17-18


Valves are semi-elliptical with a smoothly arched dorsal margin, ventral margin with a central tumid expansion. Valve ends are cuneate and ventrally curved. Axial area is narrow. Raphe is positioned near the ventral margin. The raphe is arched, with proximal raphe ends deflected dorsally. The dorsal fascia is distinct, square shaped and extends from the axial area to the dorsal valve margin. Ventral fascia is distinct, and longer (apically) than the dorsal fascia by the equivalent of 2-3 striae. Dorsal striae are punctate, parallel in the central area to slightly radiate at the apices. Ventral striae composed of a single row of areolae, slightly radiate in the central area becoming convergent at the apices.

Original Description

Author: W.Sm. 1953
Length Range: µm
Striae in 10 µm:

Original Description

F.V. elliptical or oval; V. marked with a transverse band; striae 64 in .001’. v.v.

Original Images

Cite This Page:
Stepanek, J. (2011). Amphora minutissima. In Diatoms of the United States. Retrieved April 25, 2018, from

Species: Amphora minutissima

Contributor: Joshua Stepanek

Reviewer: Rex Lowe


Smith, W. (1853). Synopsis of British Diatomaceae. John Van Voorst, London 1853. 89 pp., pls 1-31.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Amphora minutissima CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Often epiphytic