Desmatractum West & G.S West, 1902
Holotype species: Desmatractum plicatum West & G.S.West
Original publication and holotype designation: West, W. & West, G.S. (1902). A contribution to the freshwater algae of Ceylon. Transactions of the Linnean Society of London, Botany, Series 2, 6: 123-215, pls 17-22.
Request PDFDescription: Unicellular, microscopic algae with spherical to ellipsoid protoplasts enclosed in fusiform, elongated and equatorially bipartite cell envelopes. Overall cell size 17-134 x 3-18 &m. Cell envelopes with or without a median constriction and one or three transverse ribs. Cell envelope with 4 to 20 longitudinal ridges. Cells uninucleate; single chloroplast parietal and cup-shaped with one or two pyrenoids. Pyrenoids divided into two hemispheres by thylakoids, with cap of starch. Reproduction observed only in two species. Asexual reproduction by zoospores, liberated by transverse rupture of envelope in equatorial region; 4 per sporangium. Nonliberated zoospores may become aplanospores. Zoospores oval to elongate and biflagellate, with single chloroplast and eyespot; flagella equal, directed anteriorly. Sexual reproduction unknown. Desmatractum in plankton or pseudoperiphyton in freshwater; cosmopolitan, some species very common and others very rare. Found in oligotrophic to mesotrophic lakes or moorland pools, in wide range of pH (3.5-8.5). Ultrastructural studies of cell division show a phycoplast. Protoplasts have thick cell walls connected to cell envelope by bands of microfibrils. One species reported with very long, coiled and unusual bacteria-like cytoplasmic endosymbionts. Species distinguished based on cell size and number and morphology of cell envelope ribbing. To date, culture studies not successful. Some species have apparently similar forms at light microscope level that differ ultrastructurally; this will require taxonomic revision. The creation of a new genus may be necessary to separate species with irregularly formed envelope (i.e. D. bipyramidatum) from other taxa (i.e. D. indutum). D. nyanzae (Woloszynska) West has nothing to do with Desmatractum and should stay as Peniococcus nyanzae Woloszynska.
Information contributed by: O.L. Reymond & D. Garbary. The most recent alteration to this page was made on 2017-05-02 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Chlorococcales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 232-264. Ruggell: A.R.A. Gantner Verlag K.-G..
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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera,
organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA)
and intended to be published in CD format.
These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above.
The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.
Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.
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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 02 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
