Chroomonas Hansgirg, 1885

Holotype species: Chroomonas nordstedtii Hansgirg

Currently accepted name for the type species: Cryptomonas nordstedtii (Hansgirg) Senn

Original publication and holotype designation: Hansgirg, A. (1885). Anhang zu meiner Abhandlung "Ueber den Polymorphismus der Algen". Botanisches Centralblatt 23: 229-233.

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Description: Free-swimming, elliptic, biflagellate monads that often form thickly mucilaginous, palmelloid colonies. Lacking a furrow, the cells have a longitudinal, tubular gullet that extends posteriorly from the subapical vestibulum. The gullet is lined, usually, with two to four longitudinal rows of ejectisomes. Single chloroplast, pyrenoid and nucleomorph; the chloroplast containing the phycobiliprotein, Cr-phycocyanin 645 (and, rarely, Cr-phycocyanin 630), and varying in color from sky blue to blue-green and green. With or without an eyespot. Periplast with inner and superficial plates sandwiching the plasma membrane. Sexual reproduction is unknown, reproduction being by simple cell division often in the palmelloid state. Cyst production is unknown. The ultrastructure of several species has been examined. The inner periplast plates are rectangular and have strong attachment sites to the plasma membrane along their posterior margins. The superficial periplast plates are also rectangular and composed of small subunits in a crystalline arrangement and surrounded by lax fibrillar borders. The nucleomorph is not associated with the pyrenoid. The matrix of the pyrenoid is traversed by one or two pairs of thylakoids. The eyespot is located on an isolated medial lobe of the chloroplast and has an associated vacuolar system. The flagella possess an imbricate layer of rosulate scales. Mitosis and cytokinesis have been examined in Chroomonas africana. The genus has a cosmopolitan distribution in both marine and freshwater habitats, every continent. Some fifty species have been assigned to the genus but it is likely that after revision the number will be greatly reduced. Most species are described from European waters and many are known only from their type localities. Butcher (1967) extended the definition of the genus to include red-brown species and this approach was also adopted by Bourrelly (1970) and Starmach (1974), but has not been followed in more recent taxonomic treatments (Santore 1984, Hill 1991).

Information contributed by: D.R.A. Hill. The most recent alteration to this page was made on 2017-05-26 by M.D. Guiry.

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

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.

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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=43570

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024