Pleurodiscus J.W.Barker & S.H.Meakin, 1944, nom. illeg.

Holotype species: Pleurodiscus pantocsekii J.W.Barker & S.H.Meakin

Currently accepted name for the type species: Pleurodiscina pantocsekii (J.W.Barker & S.H.Meakin) P.C.Silva

Original publication and holotype designation: Barker, J.W. & Meakin, S.H. (1944). New genera and species of diatoms from Russia. Journal of the Quekett Microscopical Club, Series 4 1(6): 251-255, pls 38, 39.

Fossil: This is a genus of fossil species, or a genus with a fossil type species, or a genus the type species of which was originally described as a fossil.

Description: Thalli branched or unbranched, forming skeins of intertwining uniseriate filaments. Cells 18-26 µm in diameter, several times as long; cell wall two-layered with inner cellulose, outer mucilage layer; end walls plane; rhizoids present; no flagellated stages. Mucilage sheath may be quite thick. Cells uninucleate; chloroplasts two per cell, disc-shaped and oriented at various angles to each other; nucleus central between chloroplasts. Life cycle haplobiontic, meiosis zygotic. Sexual reproduction by scalariform conjugation; physiologically anisogamous. Zygospores ovoid to ellipsoid; develop within sporangium formed by one gametangium and portion of conjugation tube; spore wall scrobiculate (small pits in surface). Pleurodiscus poorly known; described from Puerto Rico and Ivory Coast. Trait of conjugation places in Zygnematales, but otherwise phylogenetic position unclear. Suggestion has been made that disc-shaped chloroplasts are expanded form of pillow-shaped plastids found in Zygogonium, which would thus contain monospecific Pleurodiscus. Thalli branched or unbranched, forming skeins of intertwining uniseriate filaments. Cells 18-26 µm in diameter, several times as long; cell wall two-layered with inner cellulose, outer mucilage layer; end walls plane; rhizoids present; no flagellated stages. Mucilage sheath may be quite thick. Cells uninucleate; chloroplasts two per cell, disc-shaped and oriented at various angles to each other; nucleus central between chloroplasts. Life cycle haplobiontic, meiosis zygotic. Sexual reproduction by scalariform conjugation; physiologically anisogamous. Zygospores ovoid to ellipsoid; develop within sporangium formed by one gametangium and portion of conjugation tube; spore wall scrobiculate (small pits in surface). Pleurodiscus poorly known; described from Puerto Rico and Ivory Coast. Trait of conjugation places in Zygnematales, but otherwise phylogenetic position unclear. Suggestion has been made that disc-shaped chloroplasts are expanded form of pillow-shaped plastids found in Zygogonium, which would thus contain monospecific Pleurodiscus.

Information kindly contributed by R.M. McCourt and R.W. Howshaw but may now be outdated.

Taxonomic status: This name is currently regarded as a synonym of Pleurodiscina.

Most recent taxonomic treatment adopted: Silva, P.C. (1970). Remarks on algal nomenclature. IV. Taxon 19: 941-945.

Loading names...
Loading notes...
Loading common names...
Loading references...

Verification of Data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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=46979

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 11 January 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 29 March 2024

 
Currently in AlgaeBase: