Thwaites 1856 Category: Symmetrical biraphid
BASIONYM: Mastogloia smithii Thwaites 1856
Contributor: Pat Kociolek - March 2011
Length Range: 33-46 µm
Width Range: 11-13 µm
Striae in 10 µm: 15-18
Valves are elliptic-lanceolate with mostly convex sides and protracted, broadly rounded apices. The axial area is narrow, straight, and expanded into an asymmetric, elliptic to irregularly rectangular central area. The raphe is filiform, but becomes lateral at about ½ from the apices to the center. External proximal raphe ends are dilated slightly and rounded. Striae are radiate and distinctly punctate.
Valvocopulae with locules that are rectangular to irregularly-shaped chamber, present in the middle section of the band. Locules number 6-9 in 10 µm. This taxon is found in alkaline, usually standing, waters.
Basionym: Mastogloia smithii
Author: Thwaites 1856
Length Range: µm
Striae in 10 µm:
Smith, W. (1856). Synopsis of British Diatomaceae. John Van Voorst, London 1856. 2: 107pp., pls. 32-60, 61-62, A-E.