163,770 species and infraspecific names are in the database, 22,783 images, 63,043 bibliographic items, 481,350 distributional records.

Spondylosium Brébisson ex Kützing, 1849

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Streptophyta infrakingdom
Phylum Charophyta
Class Zygnematophyceae
Subclass Zygnematophycidae
Order Desmidiales
Family Desmidiaceae

Lectotype species: Spondylosium depressum Brebisson

Original publication:Kützing, F.T. (1849). Species algarum. pp. [i]-vi, [1]-922. Lipsiae [Leipzig]: F.A. Brockhaus.
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Type designated in Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.

Description: Cells small or large, compressed (biradiate) or triradiate in end view, with deep median constriction (isthmus) where semicell walls overlap. Cell united into filaments by remains of primary wall between closely appressed secondary walls at apices of adjacent cells. Filaments commonly unattached but S. pulchellum sometimes attached by long gelatinous stalk.

Cell wall generally smooth with pores scattered or arranged in lines (small conical granules on lateral semicell margin in S. rectangulare). One chloroplast per semicell, with central mass and two flattened lateral lobes (visible in apical view only) on each side in biradiate cells, or into each angle of triradiate cells. Pyrenoid single and central, or several, in lateral lobes. Nucleus in isthmus.

Asexual reproduction by cell division and new semicell formation typical of Cosmarium-type desmids (see Cosmarium). Primary walls of new semicells persist at apex to maintain cells in filament. Possible aplanospores in single cells in field sample of S. nitens.

Sexual reproduction by conjugation between cells of disintegrated filaments in at least two species. Zygotes form between gametangia; mature zygospres spherical to irregular, smooth-walled or spinose.

Information contributed by: J.F. Gerrath. The most recent alteration to this page was made on 12 Sep 2013 by M.D. Guiry.

Comments: Spondylosium has several cosmopolitan species, and species usually occur in acidic, oligotrophic lakes and ponds.

Numbers of names and species: There are 36 species names in the database at present, as well as 37 infraspecific names. Of the species names, 31 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.

References
Hall, J.D., Karol, K.G., McCourt, R.M. & Delwiche, C.F. (2008). Phylogeny of the conjugating green algae based on chloroplast and mitochondrial nucleotide sequence data. Journal of Phycology 44: 467-477.

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

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.

Created: 11 April 2002 by M.D. Guiry

Verified by: 12 September 2013 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43545

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 16 October 2021.

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