Gregory 1856 Category: Asymmetrical biraphid
BASIONYM: Gomphonema sarcophagus Gregory 1856
SYNONYM(S): Gomphonema angustatum var. sarcophagus (Gregory) Grunow | Gomphonema angustatum f. sarcophagus (Gregory) Hustedt | Gomphonema angustatum var. sarcophagus (Gregory) Cleve
REPORTED AS: Gomphonema angustatum (Reavie and Smol 1998, p. 49, Pl. 20, Fig. 14) | Gomphonema angustatum (McBride and Edgar 1998)
Contributor: Jeremy Walls - June 2016
Length Range: 27-38 µm
Width Range: 5-7 µm
Striae in 10 µm: Coarse valve: 6-8, Fine valve: 11-14
Valves are linear- to elliptic-lanceolate, with rostrate to truncate apices. Valves are asymmetric to the transapical axis, with the footpole slightly more tapered than the headpole. The axial area is distinctly linear. A stigma is present in the central area, in line with a stria. The raphe is undulate with slightly expanded proximal ends. Striae are slightly radiate to parallel, bending inward at the center of the valve. There are typically 1-2 shortened striae at the central area. Areolae are not easily visible in the light microscope, but appear larger at the center of the valve along the axial area.
The appearance of enlarged areolae in LM is due to biseriate striae, which are visible by SEM (Reichardt 1999).
Valve morphology of specimens within populations of G. sarcophagus may vary considerably, including that irregular undulations may be present along the valve margin. Additionally, the presence of Janus cells was observed with this species. Janus cells are frustules that have two morphologically different valves, often of differing stria densities. A few species of Gomphonema have been documented to produce Janus cells, including G. parvulum and G. sarcophagus (McBride and Edgar 1998, Reichardt 1999). In this study, two valve types were observed: valves with low stria densities (coarse striae) and valves with higher stria densities (fine striae). Valves with coarse striae were more commonly observed, but over 25% of examined valves (n=55) had fine striae.
Note that G. sarcophagus and G. angustatum are very similar taxa and further investigation may show that they are environmental variants and conspecific. A lectotype was designated for G. sarcophagus (Reichardt 1999).
Basionym: Gomphonema sarcophagus
Author: Gregory 1856
Length Range: 35.6 µm
Striae in 10 µm: 8-9
Gomphonema Sarcophagus, W. G. - This species occurs abundantly in the Lochleven gatherings, but it occurs also in several gatherings made near Edinburgh, and in others from Fife, Stirlingshire, Lanarkshire, and elsewhere. Indeed it would seem not to be uncommon. In form it is linear, rather narrow, the sides gently curved, so as to form a sort of shoulder at the widest part, after which it contracts a little, and again expands to a somewhat truncate extremity. The opposite end is narrower, and, with the exception of a trifling expansion at the apex, becomes continuously narrower. These things give to it very nearly the shape of a coffin. The F. V. is, as usual in this genus, cuneate. Length about .0014 inch. Striae 20 to 22 in .001”.
Hofmann, G., Werum, M. and Lange-Bertalot, H. (2011). Diatomeen im Süßwasser-Benthos von Mitteleuropa. Koeltz Scientific Books, Königstein, 908 pp.
McBride, S.A., and Edgar, R.K. (1998). Janus cells unveiled: frustular morphometric variability in Gomphonema angustatum. Diatom Research 13(2): 293-310.
Noga, T., Stanek-Tarkowska, J., Pajaczek, A., Kochman, N., and L. Peszek. 2014. (2014). Ecological assessment of the San River water quality on the area of the San Valley Landscape Park. Journal of Ecological Engineering 15(4): 12-22.
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Reichardt, E. (1999). Zur Revision der Gattung Gomphonema: Die Arten um G. affine/insigne, G. angustatum/micropus, G. acuminatum sowie gomphonemoide Diatomeen aus dem Oberoligozän in Böhmen. Annotated Diatom Micrographs. Edited by Horst Lange-Bertalot. Iconographia Diatomologica, Volume 8, A.R.G. Gantner.
Wojtal, A. (2003). Diatoms of the genus Gomphonema Ehr. (Bacillariophyceae) from a karstic stream in the Krakowsko-Czestochowska Upland. Acta Societatis Botanicorum Poloniae 72(3):213-220.
Gomphonema sarcophagus was found in periphytic samples from a kettle hole at the Freda Haffner Kettlehole State Preserve in Dickinson County, Iowa, and epiphytic samples from a small stream in Cayler Prairie, Dickinson County, Iowa. Both sampling locations had pHs near 7 and temperature near 20°C. Conductivity was 190 μS/cm in the kettle hole and 489 μS/cm in the prairie stream.
Gomphonema sarcophagus has also been found in eutrophic ponds across Europe (Hofmann et al. 2011), as well as the San River in the upper San basin of Poland (Noga et al. 2014). The species has also been found in a stream in the Dolina Kobylanska valley, Poland, which has moderate conductivity and neutral pH. It has also been recorded across Germany (Reichardt 1999). In the United States, it has been reported to inhabit primarily mesotrophic waters with moderate conductivity (Patrick and Reimer 1975).
Distribution of Gomphonema sarcophagus in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 10 June 2016.
Credit/Source: USGS BioData
Distribution of Gomphonema sarcophagus in rivers of Alaska based on the National Water Quality Assessment program. Retrieved 10 June 2016.
Credit/Source: USGS BioData
Photo of the Kettlehole, Dickinson Co., Iowa, United States in June of 2016.
Credit/Source: Image by Sylvia Lee
The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.
Results are published in:
Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.
Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.
Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.