Atractomorpha L.R.Hoffman, 1983

Holotype species: Atractomorpha echinata L.R.Hoffmann

Original publication and holotype designation: Hoffman, L.R. (1983). Atractomorpha echinata gen. et sp. nov., a new anisogamous member of the Sphaeropleaceae (Chlorophyceae). Journal of Phycology 19: 76-86.

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Description: Unicellular, spindle-shaped, coenocytic cells with linear series of large, regularly spaced, aqueous vacuoles alternating with cytoplasmic zones containing nuclei and chloroplasts. Pyrenoids usually many per cell and invaginated by cytoplasmic channels. Dense cytoplasmic plugs may occur, particularly at cell extremities. Motile reproductive cells biflagellate with flagellar apparatus including directly opposed basal bodies. Asexual reproduction through formation of large, biflagellate zoospores; occasionally aplanospores. Sexual reproduction anisogamous and/or oogamous. Gametangia develop directly from vegetative cells with little change in size and shape. Separate male and female gametangia, except for A. porcata which produces bisexual gametangia. Both male and female gametes escape through pores in gametangial walls prior to fertilization. Young zygotes invested with thin primary membrane, either with smooth surface, or with long delicate bristles. Thick-walled zygotes resistant to prolonged periods of desiccation. Zygote cell walls with species specific ornamentation; zygotes of some species bear long, curled appendages (cirri). Atractomorpha occurs in shallow, temporary, freshwater habitats subject to extended dry intervals. Species known only from few cultured isolates from dried soil samples from Texas, California and Australia. Two new (but undescribed) species isolated from soil of dry river bed in Namibia, Africa. Asexual and sexual reproduction have been compared in the various species, and the flagellar apparatus of the biflagellate male gametes ultrastructurally compared with the male gametes of Sphaeroplea. While vegetative cells of all species are spindle-shaped, those of A. starrii are additionally bifurcated at one end.

Information contributed by: L.R. Hoffman. The most recent alteration to this page was made on 2020-05-05 by M.D. Guiry.

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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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Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 05 May 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 23 April 2024