Stoermer in Reimer 1982 Category: Asymmetrical biraphid
BASIONYM: Gomphoneis eriense var. apiculata Stoermer in Reimer 1982
Contributor: Pat Kociolek - January 2011
Length Range: 33-63 µm
Width Range: 12-14 µm
Striae in 10 µm: 12-14 at the central portion of the valve, 14-15 at the poles
Valves are broadly lanceolate-clavate, with an apiculate headpole and rounded footpole. The axial area is narrow and expanded in the middle of the valve to form a rounded central area. A single stigma is present. Striae are formed by two rows of areolae arranged alternately. The striae are radiate to strongly radiate at the footpole. Longitudinal lines are present on either side of the axial area, and may be indistinct in some specimens. The apical pore field is distinct and bi-lobed. The apiculate headpole may be strongly or weakly developed, and the expanded portion of the valve (“shoulders”) near the headpole may be variable in is expression.
We exclude here the fossil specimens from Idaho cited by Kociolek and Stoermer (1988) as part of their concept of this taxon. Those are interpreted as a separate species.
Distribution: Verified only in Northwest Iowa.
Basionym: Gomphoneis eriense var. apiculata
Author: Stoermer in Reimer 1982
Length Range: µm
Striae in 10 µm:
Kociolek, J.P. and Stoermer, E.F. (1988). Taxonomy, ultrastructure and distribution of Gomphoneis herculeana, G. eriense and closely related species (Naviculales: Gomphonemataceae). Proc. Acad. Nat. Sci. Phil. 140: 24-97. http://www.jstor.org/stable/4064935