Synedra
Ehrenberg 1830 Category: Araphid
TYPE SPECIES: Synedra ulna (Nitzsch) Ehrenberg
Smallest to largest - 4 taxa sorted by maximum length
Image Credit: Sarah Spaulding
CLASS: Fragilariophyceae
ORDER: Fragilariales
FAMILY: Fragilariaceae
- Vales linear to lanceolate with rounded ends
- Striae parallel
- Apical porefield present at each pole
Currently, species in Synedra are considered to be primarily marine, typified by S. balthica, which is synonomous with Synedra gaillonii (Bory) Ehrenberg. The taxon shown here is S. gaillonii. Following recent changes in the literature, elongate, needle-like freshwater species on the Diatoms of the United States site are treated in Fragilaria and Ulnaria.
Araphid genera, including Synedra, Fragilaria, Ulnaria and others, have been subject to a longstanding debate concerning nomenclature (Williams 2011). Historically, Fragilaria and Synedra were distinguished based on their growth form. Synedra included taxa that produced stellate colonies that attached to subtrates by a mucilage pad. Those taxa are now largely included in Ulnaria, but many have yet to be transferred. Compare also with the genus Fragilaria, which also includes linear, elongate valves that form ribbon-like colonies.
Cite This Page:
Spaulding, S., and Edlund, M. (2015). Synedra. In Diatoms of the United States. Retrieved September 24, 2017, from http://westerndiatoms.colorado.edu/taxa/genus/Synedra
Contributor: Sarah Spaulding | Mark Edlund - November 2015
Citations
Compère, P. (2001). Ulnaria (Kützing) Compère, a new genus name for Fragilaria subgen. Alterasynedra Lange-Bertalot with comments on the typification of Synedra Ehrenberg. In Jahn R., Kociolek, J. P., Witkowski, A. & Compère, P. (Eds.). Lange-Bertalot-Festschrift, Studies on Diatoms. A.R.G. Gantnter Verlag K.G. Ruggell. pp. 97-101.
Lange-Bertalot, H. and Compère, P. (2001). Fragilaria subgen. Ulnaria, comb. nov., the correct name of the subgenus including Synedra ulna, when treated in Fragilaria. Diatom Research 16: 103-104.
Lange-Bertalot, H. and Ulrich, S. (2014). Contributions to the taxonomy of needle-shaped Fragilaria and Ulnaria species. Lauterbornia 78: 1-73.
Morales, E.A. (2003). Fragilaria pennsylvanica, a new diatom (Bacillariophyceae) species from North America, with comments on the taxonomy of the genus Synedra Ehrenberg . Proceedings of the Academy of Natural Sciences of Philadelphia 153: 155-166.
Silva, P. and Hasle, G.R. (2006). Taxonomic and nomenclatural history of Fragilaria (Bacillariophyceae). Taxon 55: 200-202.
Siver, P.A., Hamilton, P.B., Stachura-Suchoples, K. and Kociolek, J.P. (2005). Diatoms of North America. The Freshwater Flora of Cape Cod. Iconographia Diatomologica 14: 1-463.
Williams, D.M. (2011). Synedra, Ulnaria: definitions and descriptions - a partial resolution. Diatom Research 26: 149-153.
Williams, D.M. and Round, F.E. (1986). Revision of the genus Synedra Ehrenb. Diatom Research 1: 313-339.
November 5th, 2015 - Change in genus circumscription
Previous to this update, the genus Synedra was presented on Diatoms of the US include a variety of freshwater species. For example, Synedra included taxa that produced stellate colonies that attached to subtrates by a mucilage pad. Following the establishment of Ulnaria (Kützing) Compère 2001, most freshwater species are in the process of being transferred to Ulnaria. S. Spaulding