Dimorphococcus Braun, 1855

Holotype species: Dimorphococcus lunatus A.Braun

Original publication and holotype designation: Braun, A. (1855). Algarum unicellularium genera nova et minus cognita praemissis observationibus de algis unicellularibus in genere. pp. [1]-114, 6 pls. Lipsiae [Leipzig]: apud W. Engelmann.

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Description: Thalli microscopic and multicellular, forming free-floating, spherical to oval or irregular colonies to 50-150 µm in diameter. Colonies composed of 4-celled coenobia with 16- or more- celled syncoenobia resembling colonies of Dictyosphaerium, i.e. with daughter coenobia placed at end of empty and slightly elongated cell walls and embedded in common mucilage. In many-celled syncoenobia the connecting strings (remnants of parental cell walls) mostly elongated and without definite shape, gelatinizing quickly and becoming indistinct. Daughter coenobia 4-celled, arcuate, with markedly alternating cells. Cells kidney-shaped to cordiform, in type species Scenedesmus-like, joined directly or with small bridge-like connections with walls in the middle. Cells 10-25 x 3-8 (-15) µm, with thickenings at ends. Cell walls smooth. Cells uninucleate; chloroplast parietal, massive, with 1 or 2-3 pyrenoids. Asexual reproduction by 4 autospores, released by longitudinal rupture of parental cell walls; empty cell walls gradually dissolving. Zoospores and sexual reproduction unknown. Dimorphococcus cosmopolitan but relatively uncommon in the plankton and metaphyton of small, shallow lakes and fishponds, and also in peat bogs where it is occasionally abundant. Dimorphococcus resembles the syncoenobia of Dictyosphaerium in terms of shape, the 4-celled coenobia with alternating cells in Scenedesmus and the 8-celled coenobia without mucilage of Raysiella. Genus placed by some authors in Scenedesmaceae, subfamily Dimorphococcoideae.

Information contributed by: F. Hindák & D. Garbary. The most recent alteration to this page was made on 2012-07-10 by Michael Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Hegewald, E., Wolf, M., Keller, A. Friedl, T. & Krienitz, L. (2010). ITS2 sequence-structure phylogeny in the Scenedesmaceae with special reference to Coelastrum (Chlorophyta, Chlorophyceae), including the new genera Comasiella and Pectinodesmus. Phycologia 49(4): 325-335.

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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=43504

Citing AlgaeBase
Cite this record as:
Michael Guiry in Guiry, M.D. & Guiry, G.M. 10 July 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 10 August 2022

 
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