Mougeotia C.Agardh, 1824, nom. cons.
Holotype species: Mougeotia genuflexa (Roth) C.Agardh
Original publication and holotype designation: Agardh, C.A. (1824). Systema algarum. pp. [i]-xxxvii, [1]-312. Lundae [Lund]: Literis Berlingianis [Berling].
Request PDFPrecise date of publication: Sep(?)
Description: Thalli unbranched, forming extensive skeins of intertwining uniseriate filaments. Cells cylindrical, 5 to 30 µm in diameter, much longer than wide; cell wall two-layered with inner cellulose, outer mucilage layer; end walls plane; no flagellated stages; a few species with one- or two-celled basal branches or rhizoids that anchor filament to substrate. Cell uninucleate; chloroplasts one per cell (sometimes two), axial, uncoiled, plate-like (=wide ribbon) in shape with axial row of pyrenoids. Nucleus one per cell, midway along length of cell, parietal to single chloroplast or in cytoplasmic bridge between two chloroplasts. Chromosomes (n= 24-92) typically small and dotlike (<1.5 µm). Haploid chromosome number 24 to 92. Asexual reproduction common by aplanospores and parthenospores (preempted gametes that become aplanospores). Aplanospores with essentially same wall color and morphology as sexually produced zygospores. Life cycle haplobiontic, meiosis zygotic. Sexual reproduction by conjugation, scalariform in most species, lateral in about a half dozen species. Almost all species homothallic and isogamous; both gametes usually capable of amoeboid movement; zygospore forms within conjugation tube between two gametangia, in both receptive gametangia or with part of zygospore in gametangia and part in tube; transverse sporangial walls cut off zygospore from gametangia; cytoplasmic residue remains inside spent gametangia. Filaments may adhere, sometimes genuflecting (zig-zag bending of adhering filaments); both processes apparently unrelated to conjugation and of unknown function. Zygospores variously shaped, from spheroid to ovoid to quadrangular (square-shaped with blunt corners). Zygospores and aplanospores commonly with two layers: outer chitinous and inner transparent. Earliest fossil zygospores from Carboniferous.
Information contributed by: R.M.McCourt & R.W.Howshaw. The most recent alteration to this page was made on 2022-09-26 by M.D. 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: Hess, S., Williams, S.K., Busch, A., Irisarri, I., Delwiche, C.F., de Vries, S., Darienko, T., Roger, A.J., Archibald, J.M., Buschmann, H., von Schwartzenberg, K. & de Vries, J. (2022). A phylogenomically informed five-order system for the closest relatives of land plants. Current Biology 32: 1-10.
Comments: Widespread in freshwater habitats worldwide. Filaments usually found as free-floating masses. Along with Zygnema, Mougeotia is one of three most commonly encountered genera in Zygnemataceae; however, Spirogyra by far most common. Common in some acidified lakes of Canada. No major economic uses or nuisance. Widely used in experimental studies of phytochrome-mediated movement of platelike chloroplast; in fossil studies used as marker for clean, oxygen-rich, shallow stagnant, mesotrophic water in habitats subject to seasonal warming; some species tolerant to heavy-metal pollution. Along with other conjugating green algae in Zygnematales, Mougeotia apparently member of Charophyceae, and thus related to lower land plants. Various conflicting phylogenetic hypotheses have postulated relation to other taxa with platelike or ribbonlike chloroplasts, either unicells (e.g., Mesotaenium) or filaments.
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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=43562
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 September 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 November 2024
