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Name derivation:
Classification:
Synura Ehrenberg 1834; 31 of 58 described species are currently recognized (Guiry 2012). Order Synurales; Family Mallomonadaceae Synonym Chlorodesmus F.W.Phillips 1882 Synonym Catenochrysis Perman 1955 Probably synonym Syncrypta
Morphology:
Cylindrical or spherical colony of biflagellate heterokont (two unequal flagella) cells bearing external silica scales. Cells are either divergent with intervening space or closely packed and contiguous at the periphery of colonies. The longer flagellum bears a single row of ‘flimmer’ (from German ‘flimmern’ meaning flicker or glimmer) or ‘mastigonemes, also called ‘tinsel hairs’ or ‘flagellar hairs’, that apparently originate in the cisternae of the endoplasmic reticulum. The flimmer in Synura have an average length of 17 nm (Heath et al. 1970). The shorter flagellum has no hairs. Synura spp. split the silica scales between two daughter cells, each cell of which then produces more scales until silica is depleted. Cell divisions continue even in the absence of silica, producing naked cells (Sandgren et al. 1996).
Similar genera:
Chrysosphaerella has silica spines in addition to silica scales. Syncrypta is likely a scaleless growth form of Synedra (Nicholls and Wujek 2003).
Habitat:
Similar to many planktonic chrysophycean and synurophycean genera, Synura competes well in somewhat acidic oligotrophic lakes (low phosphorus concentration).
References:
Guiry, M.D. and Guiry, G.M. 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 17 December 2012. Heath, J.B., A.D. Greenwood and H.B. Griffiths 1970. The origin of flimmer in Saprolegnia, Dictyuchus, Synura and Cryptomonas. Journal of Cell Science 7:445-461. Nicholls, K.H. and D.E. Wujek 2003. Chrysophycean algae. In: Wehr, J.D. and R.G. Sheath (Ed.). Freshwater algae of North America. Academic Press (Chapter 12). Phillips, F.W. (1884). On Chlorodesmus hispida, a new flagellated animalcule.Transactions of the Herfordshire Natural History Society 2: 92-94. Sandgren, C.D., S.A. Hall, and S.B. Barlow 1996. Siliceous scale production in chrysophyte and synurophyte algae. I. Effects of silica-limited growth on cell silica content, scale morphology, and the construction of the scale layer of Synura petersenii. J. Phycol. 32:675-692.