Cyclonexis A.C.Stokes, 1886

Holotype species: Cyclonexis annularis A.Stokes

Original publication and holotype designation: Stokes, A.C. (1886). Notices of new fresh-water Infusoria. Proceedings of the American Philosophical Society 23: 562-568.

Description: Colonies free-swimming, consisting of 4-34 cells which are compactly arranged side by side to form a circular plate with a small open space at the center. Cohesion of the cells rather loose and colonies easily break up. Cells naked, elongate-ovoid to wedge-shaped, sometimes with undulations along the peripheral edge. Each cell with 2 unequal flagella, 2 contractile vacuoles, 1-2 chloroplasts and, in one species, with stigma. Sometimes cells contain warty, highly refractive pustules (a special type of trichocyst called discobolocyst). Reproduction may involve escape of solitary cells or colony dissociation into individual celIs. A colony also may fragment into 2 equal or unequal parts. Cells divide by longitudinal fission. Stomatocysts not observed with certainty, nor sexual reproduction. Found in cold, acid freshwater, in several places in Europe and North America. Not common.

Information contributed by: H. R. Preisig. The most recent alteration to this page was made on 2021-10-11 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: Kawai, H. & Nakayama, T. (2015). Introduction (Heterokontobionta p.p.), Cryptophyta, Dinophyta, Haptophyta, Heterokontophyta (except Coscinodiscophyceae, Mediophyceae, Fragilariophyceae, Bacillariophyceae, Phaeophyceae, Eustigmatophyceae), Chlorarachniophyta, Euglenophyta. In: Syllabus of plant families. Adolf Engler's Syllabus der Pflanzenfamilien. Ed. 13. Phototrophic eukaryotic Algae. Glaucocystophyta, Cryptophyta, Dinophyta/Dinozoa, Haptophyta, Heterokontophyta/Ochrophyta, Chlorarachnniophyta/Cercozoa, Chlorophyta, Streptophyta p.p. (Frey, W. Eds), pp. 11-64, 103-139. Stuttgart: Borntraeger Science Publishers.

Comments: Kristiansen & Preisig (2001: 9) record this genus as alternately being a member of the family Ochromonadaceae Lemmerman 1899.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=44152

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 11 October 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 May 2024