Rossithidium
Bukhtiyarova and Round 1996 Category: Monoraphid
TYPE SPECIES: Achnanthes pusilla Grunow in Cleve and Grunow
Image Credit: Marina Potapova
CLASS: Bacillariophyceae
ORDER: Achnanthales
FAMILY: Achnanthaceae
- Valve outline linear, lanceolate, sometimes elongate
- Striae parallel or nearly so throughout valve length
- Axial area narrow
The valve outline is linear, elongate or lanceolate. The ends of Rossithidium are rounded. The striae are parallel throughout the valve, on both raphe and rapheless valves. The striae are variable and may be uni- or multiseriate. The axial area is narrow. The raphe is straight with expanded proximal raphe ends. Terminal raphe fissures are absent. The central area on the raphe valve varies in both size and shape. Areolae are present on the valve mantle.
Rossithidium is similar to Achnanthidium and there is some question about its merits as a separate genus. Rossithidium was established to include three linear species of Achnanthidium (Round and Bukhtiyarova 1996) including Achnanthes linearis W. Smith. However, the separation of Rossithidium from Achnanthidium may need to be re-examined (Kingston 2003). Many ecological surveys do not discriminate the species in Achnanthidium and Rossithidium.
Cite This Page:
Potapova, M., Spaulding, S., and Edlund, M. (2009). Rossithidium. In Diatoms of the United States. Retrieved June 18, 2013, from http://westerndiatoms.colorado.edu/taxa/genus/Rossithidium
Contributor: Marina Potapova | Sarah Spaulding | Mark Edlund - January 2009
Citations
Aboal, M., Puig, M.A. and Soler, G. (1996). Diatom assemblages in some Mediterranean temporary streams in southeastern Spain. Archiv fur Hydrobiologie 136: 509-527.
Finkelstein, S.A. and Gajewski, K. (2007). A palaeolimnological record of diatom-community dynamics and late-Holocene climatic changes from Prescott Island, Nunavut, central Canadian Arctic. The Holocene 17: 803-812.
Kingston, J.C. (2003). Araphid and Monoraphid Diatoms. In: Freshwater Algae of North America. Ecology and Classification (J.D. Wehr and R.G. Sheath, eds). Elsevier Science pp. 595-636.
Lange-Bertalot, H. and Krammer, K. (1989). Achnanthes eine Monographie der Gattung mit Definition der Gattung Cocconeis and Nachtragen zu den Naviculaceae. Bibliotheca Diatomologica 18, 393 pp. Cramer, Berlin, Stuttgart.
Potapova, M. (2012). New species and combinations in monoraphid diatoms (Family Achnanthidiaceae) from North America. Diatom Research 27(1): 29-42. doi:10.1080/0269249X.2011.644636
Round, F. E. and Bukhtiyarova, L. (1996). Four new genera based on Achnanthes (Achnanthidium) together with a re-definition of Achnanthidium. Diatom Research 11: 345-361.