Holotype species: Podosira moniliformis Ehrenberg
Original publication and holotype designation: Ehrenberg, C.G. (1840). Erstlich über ausgezeichnete jetzt lebende peruanische und mexikanische Meeres-Infusorien, welche mit zur Erläuterung räthselhafter fossiler Formen der Kreidebildung dienen. Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königlich-Preussischen Akademie der Wissenschaften zu Berlin 1840: 157-162.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Round, F.E., Crawford, R.M. & Mann, D.G. (1990). The diatoms biology and morphology of the genera. pp. [i-ix], 1-747. Cambridge: Cambridge University Press.
Description: Cells spherical to sub-spherical, single or united in pairs or rarely triplets. Approximately 12 irregularly discoid plastids. Benthic, attached by several thick polysaccharide stalks to seaweeds. Valves hemispherical or watch-glass-shaped; no distinct valve mantle; some species have a flat central area. Areolae loculate, arranged in decussate rows within radial sectors. Valve thick, the narrow loculi opening to the outside by pores that are often too small to be visible even with the SEM; to the inside the loculi open through what appear to be small open foramina but which in fact contain rotae. The edge of the valve is smooth. Rimoportulae are scattered over the whole of the valve. Their simple openings often provide the only markings on the outside; internally they are small oval structures without stalks. The rimoportulae replace areolae; their apertures are not aligned in any particular direction. Copulae numerous, narrow, with simple longitudinal slits. The valvocopula lacks slits and inserts against a shallow shelf on the valve edge.The most recent alteration to this page was made on 19 Oct 2011 by M.D. Guiry.
Comments: Characterisation of this genus and its relationship to Hyalodiscus needs further examination. For example, P. stelliger was removed from Hyalodiscus by A. Mann (1907) but its clear area of the valve face and well-marked areolae arranged in fascicles suggest it should be returned to its original genus. Bullulate (Hyalodiscus) and non-bullulate (Podosira) loculate systems may be valid differences between the genera.
Numbers of names and species: There are 69 species names in the database at present, as well as 7 infraspecific names. Of the species names, 16 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.
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: 19 October 2011 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44440
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 09 December 2019.