Polytoma Ehrenberg, 1831
Holotype species: Polytoma uvella Ehrenberg
Original publication and holotype designation: Ehrenberg, C.G. (1831). Animalia evertebrata exclusis insectis Series Prima cum tabularum decase prima. In: Symbolae physicae. (Hemprich, P.C. & Ehrenberg, C.G. Eds), pp. [1-71]. Berolini [Berlin]: ex officina academica.
Request PDFDescription: Unicellular thalli ovate, ellipsoidal, or spherical. Protoplast is colorless and contains a leucoplast. Two isokont, anterior flagella. Pyrenoids absent but starch granules present in abundance. Stigma present or absent. Two to four contractile vacuoles inserted at the apex near the flagella. Cell wall present, occasionally exhibiting longitudinal striae. Cell wall may be covered with a fine gelatinous coat. A papillum may absent or present. Asexual reproduction by zoosporogenesis. Four to eight daughter cells produced. Sporangium retains parental flagella and motility during cell division. Division plane may be longitudinal or transverse. Aplanospores have been reported. Palmella, akinete, and amoeboid stages have also been reported. Sexual reproduction isogamous, anisogamous, or oogamous depending on the species. Gametes observed to possess cell wall. Fusion occurs through pairing at the apices with the formation of a protoplasmic bridge. Gamete walls ultimately lost, followed by the development of the zygote which often accumulates "haematochrome." Zygote germinates to produce four to eight products of reduction division. Cell wall in Polytoma uvella of the type II lattice similiar to Brachiomonas, Chlorogonium, Chloromonas, Carteria and some species of Chlamydomonas.
Information contributed by: M. Buchheim. The most recent alteration to this page was made on 2024-02-19 by E.A. Molinari Novoa.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as neuter.
Most recent taxonomic treatment adopted: Masjuk, N.P., Lilitska, G.G. & Kapustin, D.O. (2011). Chlamydomonadales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 157-218. Ruggell: A.R.A. Gantner Verlag K.-G..
Comments: Polytoma is often referred to as a "colorless Chlamydomonas" in that it resembles Chlamydomonas in many respects. Polytoma uvella has been found in rain water pools that contain decaying vegetation. Many species are known largely or exclusively from culture. Polytoma has been collected world-wide. Lang undertook an ultrastructural study of P. obtusum and was the first to demonstrate the stellate structure of the flagellar transition region. Gaffal, Gaffal and Kreutzer, and Gaffal and Schneider have also examined P. papillatum at the ultrastructural level. Molecular data suggest an alliance with Chlamydomonas (Vernon-Kipp and Birky)
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Contributors
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=44236
Citing AlgaeBase
Cite this record as:
E.A. Molinari Novoa in Guiry, M.D. & Guiry, G.M. 19 February 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 November 2024
