Surirella iowensis
Lowe 1973 Category: Surirelloid
BASIONYM: Surirella iowensis Lowe 1973
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Jonathan English | Marina Potapova - March 2011
Length Range: 21-54 µm
Width Range: 15-33 µm
Striae in 10 µm: 16-26
Description
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.
Original Description
Basionym: Surirella iowensis
Author: Lowe 1973
Length Range: 17-54 µm
Width Range: 10-25 µm
Striae in 10 µm: 18
Original Description
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.
Original Images
Cite This Page:
English, J., and Potapova, M. (2011). Surirella iowensis. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/surirella_iowensis
Species: Surirella iowensis
Contributor: Jonathan English | Marina Potapova
Reviewer: Rex Lowe
Image Credit: Jonathan English, Marina Potapova
- Keel low, alar wings absent
- Valves heteropolar
- Valves slightly twisted about the apical axis
- Valves 21-54 μm long, 15-33 μm wide
- Fibulae 6-8 in 10 μm
Valves are heteropolar, with a broadly rounded headpole and a cuneately rounded footpole in the larger valves and a broadly rounded footpole in the smaller valves. The valve face is slightly concentrically undulate and twisted about the apical axis. Fibulae are 6-8 in 10 μm and costae are 16-26 in 10 μm.
Compare
Surirella iowensis is very similar to S. brebissonii and S. ovalis, except that S. iowensis is torsioned about the apical axis. Under the SEM, the rows of areolae of S. iowensis can be seen to decrease in number from 3-4 to 1-2 toward the apical axis. In contrast, S. brebissonii and S. ovalis have constant numbers of striae on throughout the valve. Surirella iowensis also differs from S. ovalis by its broadly rounded headpole in its largest valves while S. ovalis has a cuneately rounded headpole.
Surirella brebissonii
Surirella ovalis
Citations
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.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 65058