Home / Cyanobacteria / Filaments / Unbranched / Tapered / Raphidiopsis
Click on images for larger format
Name derivation:
Classification:
Raphidiopsis F.E.Fritsch and F.Rich 1929; 8 of 9 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013). Order Nostocales; Family Nostocaceae
Morphology:
Solitary trichomes tapered toward both ends lack sheaths. Trichomes straight, waved or helical. Crosswalls only slightly 'incut' (constricted) or not observable. Multiple ntercalary akinetes form adjacent each other in strings.
Similar genera:
Cylindrospermopsis raciborskii is essentially identical in light microscopy until it forms a terminal heterocyst (not formed in Raphidiopsis). Raphidiopsis (cyanobacteria, Nostocaceae) is difficult to parse from unicellular Ankistrodesmus (Price 2017, personal communication). In fresh samples Ankistrodesmus has a brighter green color, but with such small cells color distortion occurs in microscopy. In samples preserved with Lugol’s Solution the color difference is not apparent. When preserved with formalin or formalin-sugar solution the pigments are bleached.
Habitat:
Freshwater plankton; occasionally forms light blooms, often most concentrated at depths of 1 -3 m (Marin 2010)
References:
Guiry, M.D. and G.M. Guiry 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 28 February 2013. Marin, K.S.S. 2010. Physiogenomics of Cylindrospermopsis raciborskii and Raphidiiopsis brookii (Cyanobacteria) with emphasis on evolution, nitrogen control and toxin biosynthesis. Doktors der Naturwissenschaften (Dr. rer. Nat.), Faculty of Biology and Chemistry, University Brenem, Germany (May 2010). Price, K. 2016. Microbiologist, Department of Environmental Protection. Bureau of Laboratories, 2575 Interstate Dr., Harrisburg, PA 17110