150,309 species and infraspecific names are in the database, 20,442 images, 57,825 bibliographic items, 380,995 distributional records.

Melosira C.Agardh, 1824, nom. cons.

Classification:
Empire Eukaryota
Kingdom Chromista
Phylum Bacillariophyta
Subphylum Coscinodiscophytina
Class Coscinodiscophyceae
Subclass Melosirophycidae
Order Melosirales
Family Melosiraceae

Holotype species: Melosira nummuloides C.Agardh

Original publication and holotype designation: Agardh, C.A. (1824). Systema algarum. pp. [i]-xxxvii, [1]-312. Lundae [Lund]: Literis Berlingianis [Berling].
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Stoermer, E.F. & Julius, M.L. (2003). Centric Diatoms. In: Freshwater Algae of North America. (Wehr, J.D. & Sheath, R.G. Eds), pp. 559-594. San Diego: Academic Press.

Nomenclatural notes
The orthography "Melosira" has also been conserved. - (19 Oct 2015) - M.D. Guiry

Description: Cells cylindrical to subsperical, united in filaments by mucilage pads secreted onto their valve faces; in addition irregular spines may assist the linkage. Cells united distinctively into pairs or triplets by their cingula. Plastids lobed, small plate-like, lying in the peripheral cytoplasm. A common genus in freshwater (M. varians) and marine epibenthic habitats (M. nummuloides, M. moniliformis). Valve face flat or domed, covered with small spines or granules; a more or less well-developed corona consisting of larger irregular spines is sometimes developed. This may be surrounded by a carina (a flat collar-like structure) as in M. nummuloides. Valve mantle not readily distinguishable from valve face in most species. Valve mantle edge having a milled appearance. The valve structure is loculate, the loculus being open to the outside via a number of small simple pores and to the inner surface by somewhat larger pores, which may be partially or completely bridged by silica struts (in the latter instnace forming rotae). The pattern of these inner pores is independent of the loculi (cf. Stephanopyxiz). The loculi may be randomly arranged or lie in rows radiating from the centre of the valve. Rimoportulae occur usually in a ring near the mantle edge and sometimes scattered or grouped on the valve; there is a circular external aperture surrounded by an irregular rim. The internal apertures are in the form of elongate slits also surrounded by an irregular, low rim. Copulae split, ligulate, with regular longitudinal rows of small pores; pars media distinct and near advalvar edge. The two valves are closely associated during the greater part of the cell cycle and the cingula of adjacent daughter cells overlap one another considerably.

The most recent alteration to this page was made on 19 Oct 2015 by M.D. Guiry.

Comments: The genus as conceived by previous workers has included a great range of taxa, some of which have been transferred to other genera (see Aulacoseira, Paralia, Orthoseira and Ellerbeckia). For reference on Melosira and related genera see Crawford, 1988.

Numbers of names and species: There are 366 species names in the database at present, as well as 396 infraspecific names. Of the species names, 57 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):

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

References
Hustedt, F. (1930). Bacillariophyta (Diatomeae) Zweite Auflage. In: Die Süsswasser-Flora Mitteleuropas. Heft 10. (Pascher, A. Eds), pp. [i]-vii, [1]-466. Jena: Verlag von Gustav Fischer.

Hasle, G.R. & Syvertsen, E.E. (1996). Marine diatoms. In: Identifying Marine Phytoplankton. (Tomas, C.R. Eds), pp. 5-385. San Diego: Academic Press.

Scott, F.J. & Thomas, D.P. (2005). Diatoms. In: Antarctic marine protists. (Scott, F.J. & Marchant, H.J. Eds), pp. 13-201. Canberra & Hobart: Australian Biological Resources Study; Australian Antarctic Division.

Crawford, R.M. (1979). Taxonomy and frustular structure of the marine centric diatom Paralia sulcata. Journal of Phycology 15(2): 200-210.

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: 19 October 2015 by M.D. Guiry

Linking to this page: http://algaebase.org/search/genus/detail/?genus_id=Jf3087698f2d1cee8

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 16 January 2018.

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