163,469 species and infraspecific names are in the database, 22,770 images, 62,968 bibliographic items, 480,353 distributional records.

Pseudoguinardia von Stosch, 1986

Empire Eukaryota
Kingdom Chromista
Phylum Bacillariophyta
Subphylum Coscinodiscophytina
Class Coscinodiscophyceae
Subclass Coscinodiscophycidae
Order Coscinodiscales
Family Hemidiscaceae

Holotype species: Pseudoguinardia recta Stosch

Original publication and holotype designation: Stosch, H.A. von (1986). Some marine diatoms from the Australian Region, especially from Port Phillip Bay and tropical North-eastern Australia. II* Survey of the Genus Palmeria and of the Family Lithodesmiaceae including the new genus Lithodesmioides. Brunonia 9: 57-74.

Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Tomas, C.R., Eds (1996). Identifying marine diatoms and dinoflagellates. pp. 1-858. San Diego: Academic Press Inc.

Description: Colonies up to 17 cells long, cylindrical and straight, separable but not dissociating upon fixation and, apart from pervalvarly rectangular notches, without intercellular spaces. Cells in girdle view rectangular, with gently rounded corners and flat valves; pervalvar axis deep; the only distinctive structure in girdle view a large rimoportula at the base of every mantle, which are situated on the same side of the colony. Chromatophores globular, numerous; each chromatophore with large pyrenoid. Valves circular, flat, with scattered poroids on valve face and mantle and marked by a low elliptical submarginal ridge which appears to separate the valve face from low mantle. A large rimoportula located on mantle, close to valve face; appears as a ca 1_m long slit flush with the surface of the mantle, but surrounded by a protruding siliceous thickening; slit parallel or somewhat oblique to valvar plane; a small flap from the mantle (false antiligula) extends over the large rimoportula. A ring of small rimoportulae locataed somewhat more distally on mantle; slits ca 200 nm long and parallel to pervalvar axis. A pseudonodulus, ca 3 _m, with one to several pores, located on periphery of valve face, appears as slight circular elevation. Valve bilaterally symmetrical about a diameter that connects large rimoportula with pseudonodule. A 'fontanelle', faintly visible by LM on valve face, variable in shape but coinciding grossly with symmetry axis, confined by low costae on long sides and extending near marginal ridge; interior of fontanelle marked by scattered poroids and short, irregular costae with stubby branches that may or may not connect with fontanelle-defining costae; numerous narrow, branched or unbranched costae extend from submarginal ridge towards center of valve face. Cingulum composed of numerous open bands; openings and ligulae form two opposite rows. Valvocopula lacks ligula and antiligula, a shallow excision accomodates false antiligula of valve. Most copulae with blunt or bifurcated ligula and no antiligula. Plurae, more delicate and narrower than other bands, with antiligulae. Planktonic in warmer water's of world's oceans.

Information contributed by: M.C. Amspoker. The most recent alteration to this page was made on 13 Feb 2011 by M.D. Guiry.

Numbers of names and species: There is only one species or infraspecific name in the database at present, which has 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):

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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: 26 April 2003 by Mairead Murphy

Verified by: 13 February 2011 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=46448

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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 28 September 2021.

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