Acanthosphaera Lemmermann, 1899
Holotype species: Acanthosphaera zachariasii Lemmermann
Original publication and holotype designation: Lemmermann, E. (1899). Das Phytoplankton sächsischer Teiche. Forschungsberichte aus der Biologischen Station zu Plön 7: 96-135, pls I, II.
Description: Unicellular algae with spherical cells 8-15 &m diameter with 20-40 radially arranged spines. Spines 20-70 &m in length, pointed at tips with expanded conical, hollow base. Cells uninucleate; single chloroplast parietal and cup-shaped; single pyrenoid prominent with distinct starch sheath and with numerous, finger-like cytoplasmic extensions. Asexual reproduction by biflagellate zoospores, 2, 4 or 8 per sporangium; released by rupture of parental wall in common membrane. Zoospores ovoid often with 2 stigmata and four contractile vacuoles. Sexual reproduction unknown. Acanthosphaera planktonic in freshwater ponds and lakes; essentially cosmopolitan with records from Europe, Asia and North America, mostly in temperate climates. Type species widely distributed, but A. tenuispina known only from Charkov in former USSR. Ultrastructural and chemical studies of spines and cell wall show complex construction with specialized arrangement of fibrils, 3-4 nm subfibrils, 200-300 nm long spicules on the spines. Spines consist mostly of stiff, parallel, non-crossbanded fibrils. Spines form on incompletely developed cell walls but only after glycoproteidic outer layer deposited. Species distinguished based on cell size, and spine length and morphology. Relationships of genus within family will require further ultrastructural studies.
Information contributed by: D. Garbary. The most recent alteration to this page was made on 2020-11-14 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Trebouxiophyceae. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 61-108. 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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=45037
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 14 November 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 28 January 2023