Euastropsis Lagerheim, 1895

Holotype species: Euastropsis richteri (Schmidle) Lagerheim

Original publication and holotype designation: Lagerheim, G. (1895). Studien über arktische Cryptogamen. I. Über die Entwickelung von Tetraédron Kütz. und Euastropsis Lagerh., eine neue Gattung der Hydrodictyaceen. Tromsø Museums Årshefter 17(III): 1-24.

Description: Thalli colonial, 10-40 x 6-25 &m, consisting of two-celled, free-floating coenobia. Cells 5-20 x 4.5-25 &m, triangular or trapezoidal with opposed bases of cells mutually flattened, distal ends deeply notched. Cells walls smooth. Cells uninucleate; chloroplasts single and parietal with single pyrenoid. Asexual reproduction by coenobial formation involving repeated divisions of protoplast into 4, 8, 16 or 32 biflagellate zoospores; zoospores release as a group through tear in cell wall; spores in common vesicle which remains attached to parent cell wall. Zoospores show some movement in vesicle but round up and become joined in pairs forming 1-16 new coenobia. Vesicle persists for short periods after coenobia form. Sexual reproduction unknown. Euastropsis planktonic in diversity of freshwater ecosystems; reported from Europe, Africa and North and South America. Euastropsis differs from Pediastrum in the formation of multiple coenobia from a single parental cell and in the occurrence of only 2-celled coenobia.

Information contributed by: D. Garbary & T. Harper. The most recent alteration to this page was made on 2015-02-05 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Sphaeropleales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 280-355. Ruggell: A.R.A. Gantner Verlag K.-G..

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=44255

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 05 February 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 13 December 2024