Home / Cyanobacteria / Filaments / Unbranched / Untapered / No_heterocysts / No_visible_sheath / Romeria

Home button

 

 

 

 

 

Click on images for larger format

Name derivation:

 

Classification:

Romeria  Koczwara ex Geitler  1932;  15 of 20 species descriptions are currently accepted taxonomically (Guiry and Guiry 2013).

Order Pseudanabaenales;  Family Pseudanabaenaceae

Synonyms according to Komárek (2001):

Synonym:  Raciborskia Koczwara 1929

Synonym:  Amalia De Toni 1934

Synonym:  Campylotropium Hortob. et Hilliard 1965

 

Similar genera:

Coccoid genera Synechococcus and Rhabdoderma have ‘very similar’ cell morphology and cell division;  Aphanothece strains have ’almost identical’ thylakoid arrangement (Komárek 2001).

 

Morphology:

Filamentous and pseudofilamentous; trichomes solitary or rarely in microscopic colonies, free-floating, fine, few-celled, disintegrating to solitary cells, unbranched, irregularly to screw-like coiled, with sometimes freely connected cells by their ends, without sheaths (but enveloped usually by very fine, diffluent, colorless, slightly visible mucilaginous envelopes’ when stained), always, isopolar, 0.6-3 μm wide, incut (constricted) at the cross walls, end cells not attenuated, immotile. Cells elongated, cylindrical, always longer than wide (usually several times), cut or rounded at the ends, without aerotopes; end cells cut or rounded. Cell content pale blue-green, greyish or yellowish, usually homogeneous.  No heterocysts, akinetes, or gas vesicles (Guiry and Guiry 2013).  No sheath (Komárek 2001)

 

Nitrogen preference:

In mesocosms mimicking commercial shrimp ponds, Romeria preferred ammonium but utilized urea (dissolved organic nitrogen) as well as dinoflagellates.  Nitrate and bio-available phosphate levels remained low during experiments where either N15-ammonium chloride or N15-urea were added to 1 L incubation bottles (Burford 2005).

 

Habitat:

Freshwater plankton in meso- to eutrophic lakes, reported only from northern hemisphere to date.  One marine species (R. Mexicana) reported from Gulf of Mexico.  Also marine plankton.

 

 

References:

Burford, M.A.  2005.  Relative uptake of urea and ammonium by dinoflagellates or cyanobacteria in shrimp mesocosms.  Hydrobiologia 549:297-303.

Geitler, L.  1932.  Cyanophyceae. In:  Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. (Rabenhorst, L. Eds) Vol. 14, pp. 673-1056.  Leipzig: Akademische Verlagsgesellschaft.

Guiry, M.D. and G.M. Guiry  2013.  AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.  http://www.algaebase.org; searched on 22 May 2013.

Komárek, J.   2001.  Review of the cyanoprokaryotic genus Romeria.  Czech Phycology, Olomouc 1:5-19.

 

 

 

Home / Cyanobacteria / Filaments / Unbranched / Untapered / No_heterocysts / No_visible_sheath / Romeria