Octosporiella Kugrens, 1984

Holotype species: Octosporiella coloradoensis Kugrens

Original publication: Kugrens, P. (1984). Octosporiella coloradoensis gen. et sp. nov., a new tetrasporalean green alga from two Colorado mountain lakes. Journal of Phycology 20: 88-94, 14 figs.

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Description: Spherical, colonial thalli mostly to 250 &m diameter, divided into eight subcolonies each with eight cells; sometimes larger, irregular aggregations produced. Subcolonies with individual sheaths and entire colony with sheath 10-15 &m thick. Cells spherical, to 10 &m diameter with two pseudoflagella to ca 150 &m long that project beyond colony sheath. Cells uninucleate with two anterior contractile vacuoles; single, parietal chloroplast cup shaped, with single pyrenoid and no stigma. Asexual reproduction typically by daughter colony formation via autospore production (eleutheroschisis). New daughter colonies initiated by shedding of pseudoflagella and expansion of subcolony matrix with subsequent separation of sub colony cell octad. Cells remain as aplanospores or are converted into 'zoospores' with formation of rigid 'flagella' to 26 &m long extending almost at right angles to cell axis. Each parent cell expands and synchronous or asynchronous division occurs within each cell of subcolony to produce eight spores. Spores then develop new pseudoflagella. With each reproductive cycle the subcolony sheath becomes the new colony sheath as the former colony fragments. Akinetes to 20 &m in diameter formed in culture after nutrient depletion. Akinetes initiated by cell enlargement and formation of thick sheaths. During germination the sheath expands and becomes the new colony sheath and akinete divides to form eight aplanospores (10-14 &m diameter) with each aplanospore forming own wall. The role of akinetes in nature unknown. Sexual reproduction not observed. Octosporiella planktonic in alkaline mountain lakes; reported from Colorado with collections made only during October/November. Octosporiella similar to Paulschulzia which has variable numbers of cells and liberated zoospores. Occurrence of zoospores equivocal, and ultrastructural studies required to characterize pseudoflagella.

Information contributed by: D. Garbary & P. Kugrens. The most recent alteration to this page was made on 2004-08-19 by Robert Wilkes.

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

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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.

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Citing AlgaeBase
Cite this record as:
Robert Wilkes in Guiry, M.D. & Guiry, G.M. 19 August 2004. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 April 2024