160,132 species and infraspecific names are in the database, 22,604 images, 62,233 bibliographic items, 471,453 distributional records.

Tetraselmis F.Stein, 1878

Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Chlorophyta infrakingdom
Phylum Chlorophyta
Subphylum Chlorophytina
Class Chlorodendrophyceae
Order Chlorodendrales
Family Chlorodendraceae

Holotype species: Tetraselmis cordiformis (H.J.Carter) F.Stein

Original publication and holotype designation:

Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Moestrup, Ø. (2002). Phylum Prasinophyta. In: The Freshwater Algal Flora of the British Isles. An identification guide to freshwater and terrestrial algae. (John, D.M., Whitton, B.A. & Brook, A.J. Eds), pp. 281-286. Cambridge: Cambridge University Press.

Nomenclatural notes
Derivation of name: tetra, four; selmis, an angler's noose made of hair (Liddle & Short). - (1 Oct 2015) - M.D. Guiry

Description: Unicellular flagellates. Cells more or less compressed, often slightly curved but never twisted. Cells cordiform, elliptical or almost spherical. Anterior end with invagination, 4 equal flagella in 2 opposite pairs. The cell contains a single more or less cup-shaped chloroplast (very rarely two chloroplasts), usually with a central pyrenoid. A single eyespot is present, located on one of the flattened sides of the cell, the position depending on the species. Freshwater species contain two anterior contractile vacuoles. Cell surrounded by close-fitting periplast of fused scales. The flagella covered by square/diamond-shaped scales in 24 rows overlaid by 24 double rows of scales. Two rows of hair-shaped scales project from opposite sides of the flagella. Asexual division in the non-motile stage. In many species one of the daughter cells inverts within the parent periplast, the 2 daughter cells then lie in reversed positions. In the non-motile stage new walls develop, old walls accumulating as concentric rings around the cell or being polarized on one side, forming a stalk. The stalks may be long and occasionally branched. Sexual reproduction unknown. Vegetative thick walled cysts known in several species. These germinate by division into 4 cells. The species differ in cell shape, size, presence or absence of pyrenoids, chloroplast morphology, etc., but many of these features have been poorly described and the taxonomy of the genus is in a state of confusion. More recently the ultrastructure of the pyrenoid has been suggested as a taxonomic marker (Hori and others 1982) and, more recently, the detailed structure of the flagellar hair scales (Marin and others 1993). Some species of Tetraselmis occur in plankton, others are benthic, colonizing sand and a few occur as endosymbionts in metazoans, e.g. in the acoel turbellarian Convoluta (Provasoli and others 1968; Yamasu 1982). Mitosis described ultrastructurally by Stewart and others (1974), the flagellar apparatus by Norris and others (1980) and Melkonian (1978). Species of Tetraselmis have been used extensively in plant physiology and aquaculture (e.g. Gooday 1970; Kirst 1977; Douglas 1983; Regan 1988; Day and Turner 1992).

Information contributed by: Ø. Moestrup. The most recent alteration to this page was made on 1 Oct 2015 by M.D. Guiry.

Comments: Throndsen (1997: 654) records this genus as a member of the Phylum Chromophyta, Class Prasinophyceae, Order Chlorodendrales, Family Chlorodendraceae.

Numbers of names and species: There are 36 species names in the database at present, as well as 2 infraspecific names. Of the species names, 33 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Click here to also show infraspecific names in the list below.

Throndsen, J. (1996). The planktonic marine flagellates. In: Identifying marine phytoplankton. (Tomas, C.R. Eds), pp. 591-730. San Diego: Academic Press.

Sluiman, H.J., Guihal, C. & Mudimu, O. (2008). Assessing phylogenetic affinities and species delimitations in Klebsormidiales (Streptophyta): nuclear-encoded rDNA phylogenies and ITS secondary structure models in Klebsormidium, Hormidiella, and Entransia. Journal of Phycology 44(1): 183-195.

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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.

Created: 23 April 2002 by M.D. Guiry

Verified by: 01 October 2015 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44099

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 03 March 2021.

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