Pseudostaurosira D.M.Williams & Round, 1988
Holotype species: Fragilaria brevistriata Grunow
Currently accepted name for the type species: Fragilaria brevistriata Grunow
Original publication and holotype designation: Williams, D.M. & Round, F.E. (1988 '1987'). Revision of the genus Fragilaria. Diatom Research 2: 267-288, 58 figs.
Most recent taxonomic treatment adopted: Medlin, L.K. & Desdevises, Y. (2016). Phylogeny of 'ARAPHID' diatoms inferred from SSU & LSU rDNA, RBCL & PSBA sequences. Vie et Milieu 66(2): 129-154, 5 figs, 5 tables.
Description: Frustules symmetrical in side view, forming chains in taxa that possess spines. Taxa with incipient or no spines, presumably attached by mucilage stalks. Valves cruciform, bigibbous, lanceolate, rhombic or elliptic. Sternum of variable width and shape. Transition from valve face to mantle varies from abrupt to more gradual, with formation of a transition zone. Striae composed of one to (rarely) a few rows of wide, round, transapically elliptical, or irregularly polygonal areolae running from valve face to mantle. Internally, areolae open into a single depression running from valve face to mantle, which may become chamber-like. Volae highly branched, usually dichotomously, arising from the inner perimeter of the areolae and at different depths. Virgae rectangular or flared at their proximal and distal ends. Vimines short and wide, the one at the valve face-mantle transition usually being wider, giving the impression of a single apical rib running along the valve face margin. Viminules seldom produced and, when formed, occupying only a part of a stria. Flaps or flat siliceous growths originate from several points around the external perimeter of the areolae, close to their external surface. Concentric discs sometimes present, partially occluding the depression into which the areolae open internally. Solid spines can grow from the enlarged vimen that connects the virgae along the valve-face edge or from the virgae themselves, or they can be absent. Spines of varying shape, but usually spatulate, with or without terminal branching, with a cylindrical base, and often bearing stipulae. Stipules produced near the base of spines and projecting downward. Apical pore fields absent, reduced or more fully developed, of the ocellulimbus type; in many cases they are sunken into the apical portion of the valve. They are composed of round poroids, which are sometimes arranged along external troughs parallel to the apical axis of the valve. Mantle plaques present in many species and situated along the abvalvar edge of the valve mantle. Cingulum composed of a larger valvocopula and few to many ligulate copulae, always open, lacking fimbriae and perforations. Emend. E. Morales (2019 : 268).
Information kindly contributed by emend E. Morales in Morales <i>et al.</i> (2019). but may now be outdated.
Characters considered diagnostic of Pseudostaurosira: Wide and short vimines. Though these vimines are also found in other genera having round areolae, such as Nanofrustulum (Li et al. 2018: figs 286–289), Pseudostaurosiropsis (Morales 2001: figs 7a–d, g, i, j, l) and Sarcophagodes (Morales 2002: pl. 5, figs 1–3), in Pseudostaurosira they are wider due to transapical expansion during valve ontogeny, and shorter due to the areolae being transapically expanded, thus having their shortest axis parallel to the longitudinal axis of the vimines (Morales & Edlund 2003: figs 39, 45, Cejudo-Figueiras et al. 2011: figs 108–111, Morales et al. 2012: figs 42, 48).
Characters considered diagnostic of higher taxonomic ranks known/presumed to occur in all species of Pseudostaurosira: Rectangular or doubly flared virgae. The degree of flaring varies depending on the size reduction of terminal vimines (those located towards the axial area of the valve and towards the abvalvar edge of the mantle) and the shape of terminal areolae along a stria
Numbers of names and species: There are 89 species names in the database at present, as well as 15 infraspecific names. Of the species names, 73 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.
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.
Morales, E.A., Wetzel, C.E., Novais, M.H., Buczkó, K., Morais, M.M. & Ector, L. (2019). Morphological reconsideration of the araphid genus Pseudostaurosira (Bacillariophyceae), a revision of Gedaniella, Popovskayella and Serratifera, and a description of a new Nanofrustulum species. Plant Ecology and Evolution 152(2): 262-284, 4 figs, 1 table.
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: 25 October 2017 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44204
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 22 September 2021.