Plagiogrammopsis Hasle, Stosch & Syvertsen, 1983
Holotype species: Plagiogrammopsis vanheurckii (Grunow) Hasle, Stosch & Syvertsen
Original publication and holotype designation: Hasle, G.R., Stosch, H.A. von & Syvertsen, E.E. (1983). Cymatosiraceae, a new diatom family. Bacillaria 6: 9-156.
Description: Cells joined into short filaments in nature but long filaments in culture; the cells are only loosely attached to each other and separate easily. Rectangular in girdle view, with apical elevations and a central expansion. A slight thickening of the valve centrally indicates the presence of a pseudoseptum. One plastid, lying along the girdle. Common in the marine benthos in shallow areas; possibly associated with sand grains. Frustules heterovalvar, one valve bearing pili, the other a rimoportula. Valves lanceolate with rostrate to capitate apices, which twist slightly to opposite sides. Apices elevated, bearing small ocelluli, which are somewhat lateral. Valve face slightly domed, curving into shallow mantles. Areolae large, circular; closely spaced or sometimes in more-or-less transverse rows on the valve face; forming a single row on the mantle. Each areola is closed by a pegged cribrum, which is raised slightly above the outer surface of the valve. There is a plain area or transverse band (fascia) in the centre of the valve, but no sternum. Long thin spines occur around the edge of the valve face; some have flattened spathulate ends. One valve has long barbed pili, one arising near each ocellulus. The other valve has a small rimoportula near the centre. Both have a prominent pseudoseptum running across beneath the plain area or fascia in the middle of the valve. Girdle composed of 5-8 split copulae, which are ligulate and each have one row of fine pores.
The most recent alteration to this page was made on 2022-12-06 by Salvador Valenzuela Miranda.Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Nikolaev, V.A., Kociolek, J.P., Fourtanier, E., Barron, J.A. & Harwood, D.M. (2001). Late Cretaceous diatoms (Bacillariophyceae) from the Marca Shale member of the Moreno Formation, California. Occasional Papers of the California Academy of Sciences 152: 1-119, 39 plates.
Comments: This genus is related to Cymatosira and is distinguished from the superficially similar Plagiogramma by the presence of pili, long thin spines, a single pseudoseptum, rimoportunae, elevations bearing the ocelluli, and the absence of a sternum. Unlike some other members of the Cymatosiraceae. the degree of heterovalvy is slight.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=46027
Citing AlgaeBase
Cite this record as:
Salvador Valenzuela Miranda in Guiry, M.D. & Guiry, G.M. 06 December 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 23 April 2024
