W. Smith 1953 Category: Asymmetrical biraphid
BASIONYM: Amphora minutissima W. Smith 1953
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.
Basionym: Amphora minutissima
Author: W. Smith 1953
Length Range: µm
Striae in 10 µm:
F.V. elliptical or oval; V. marked with a transverse band; striae 64 in .001’. v.v.
Smith, W. (1853). Synopsis of British Diatomaceae. John Van Voorst, London 1853. 89 pp., pls 1-31.