Ellerbeckia R.M.Crawford, 1988
Holotype species: Ellerbeckia arenaria (D.Moore ex Ralfs) Dorofeyuk & Kulikovskiy
Original publication and holotype designation: Crawford, R.M. (1988). A reconsideration of Melosira arenaria and M. teres resulting in a proposed new genus Ellerbeckia. In: Algae and the Aquatic Environment. (Round, F.E. Eds), pp. 413-433. Bristol: Biopress.
Description: Cells large, shortly cylindrical, linked to form curved chains of up to 30 or more cells. Plastids numerous, small discoid. Mainly in freshwater, with both fossil and recent forms known. Sometimes visible to the naked eye! Valves robust, circular, with radial markings. Valve face and mantles sharply differentiated. Sibling valves different and complementary, the 'cameo' valve bearing a system of ridges and the 'intaglio' valve an equivalent system of grooves to accommodate them. Intaglio valves have a plain mantle, cameo valves a stepped mantle, as a result of the formation of the cameo valves beneath the edge of the parental hypotheca (Crawford, 1981b). The valves also have different curvatures and when the concavo-convexity is as pronounced as in E. arenaria forma teres. this results in cells of unequal pervalvar dimensions; large cells have two (convex) intaglio valves, small cells have two (concave) cameo valves, and intermediate cells have one of each. Valve face without pores except for a peripheral ring in some species. Valve mantle very thick, consisting of a massive inner layer penetrated by long tubes, which connect the cell lumen with a series of shallow chambers; these run the length of the mantle and open to the outside via a finely porous layer of silica. A unique type of tubular process is present on the mantle; these are easily seen in LM in the forma teres. Each process takes the place of a mantle tube and opens to the inside by a small pore at the top of a dome-like projection. The valvocopula is closed but the other copulae are open. All have rows of small round pores. Valvocopula not easily detached from its valve, bearing a series of crenulations which interdigitate with projections from the edge of the valve mantle.
The most recent alteration to this page was made on 2024-10-01 by G.M. 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: Khursevich, G. & Kociolek, J.P. (2012). A preliminary, worldwide inventory of the extinct, freshwater fossil diatoms from the orders Thalassiosirales, Stephanodiscales, Paraliales, Aulacoseirales, Melosirales, Coscinodiscales, and Biddulphiales. Nova Hedwigia Beiheft 141: 315-364, no figs.
Comments: Paralia has a similar valve structure and also exhibits heterovalvy, justifying its inclusion in the same family as Ellerbeckia (the Paraliaceae). Species of Ellerbeckia have been reported from marine as well as freshwater localities, providing a further link with Paralia. Moyiseeva & Genkal (1987) have recently combined taxa with Paralia that we consider find their proper place within Ellerbeckia.
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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=43736
Citing AlgaeBase
Cite this record as:
G.M. Guiry in Guiry, M.D. & Guiry, G.M. 01 October 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
