The valves are variable in size and shape and are more or less heteropolar. The headpole is broadly rounded, but the footpole varies between broadly rounded in the smaller valves and cuneately rounded in the larger valves. The valve face slightly concentrically undulate and is partially twisted about the apical axis. The fibulae are marginal and have a density of 6-8 per 10μm. The costae extend from the marginal area to the apical axial line in a density of 16-26 per 10μm. The areolae on the valve face, only visible in the SEM, are round and in rows of 1-2 near the apical axis and of 3-4 near the marginal area. There are what appear to be in the LM large areolae around the circumference of the valve but these are actually indentations in the valve face at the end of the striae.
Basionym: Surirella iowensis
Author: Lowe 1973
Length Range: 17-54 µm
Width Range: 10-25 µm
Striae in 10 µm: 18
Cells heteropolar, more or less torsioned about the transapical axis. Valves ovoid, with broadly rounded headpole and more narrowly rounded footpole, 17-54 µ long, 10-25 µ broad. wings little developed, “windows” not apparent. Wing canals 5-7 in 10 µ, extending to center of valve where they are interrupted by a narrow pseudoraphe. Surface of central portion of valve striate, striae about 18 in 10 µ.
Lowe, R.L. (1973). Notes on Iowa diatoms X: New and rare diatoms from Iowa. Proceedings of the Iowa Academy of Science 79:66-69, pl. 1-5.
Stoermer, E.F. (1963). New taxa and new United States records of the diatom genus Neidium from West Lake Okoboji, Iowa. Notulae Naturae 358: 1-9.
NADED ID: 65058