Subsilicea H.A.von Stosch & B.E.F.Reimann, 1970
Holotype species: Subsilicea fragilarioides von Stosch & Reimann
Original publication and holotype designation: Stosch, H.A. von & Reimann, B.E.F. (1970). Subsilicea fragilarioides gen. et spec. nov., Eine Diatomee (Fragilariaceae) mit vorwiegend organischer Membran. In: Diatomaceae II (J. Gerloff & J.B. Cholnoky, eds.). Beihefte zur Nova Hedwigia 31: 1-36, 8 pls.
Description: Cells firmly linked together to form long filments; oblong with rounded apices in girdle view. One plastid (rarely up to 8 according to von Stosch & Reimann, 1970). Found in the marine littoral associated with sediments but carried up into the plankton by turbulence. Valves linear to elliptical; very lightly silicified, the siliceous part comprising a central rib (sternum) from which lateral extensions traverse the valve face and continue down the valve mantle, branching at their ends. There is some indication of a ridge (upward extension) along the junction of the valve face and mantle but this is not obvious in von Stosch & Reimann's TEM sections. At the apices of the sternum there are small semi-circular areas of pores, which appear from their structure and position to be clusters of porelli forming small ocelli (ocelluli). There are no true areolae or cribra but the lightly silicified framework is supported by a relatively well-developed organic component (see von Stosch & Reimann). There are no portules or other valve organelles. The cingulum is most striking, being composed of numerous scales. Each scale has a thicker pars media and a slightly thickened abvalvar edge, the remainder being merely a delicate membrane with a fimbriate advalvar margin. The scales vary in size across the cingulum. The scale forming the valvocopula is apparently a complete hoop; the adjacent scales are elongate while the others become shorter and more numerous towards the abvalvar edge of the cingulum.
The most recent alteration to this page was made on 2011-10-20 by M.D. Guiry.Taxonomic status: This name is of an entity that is currently accepted taxonomically.
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.
Comments: Von Stosch & Reimann (1970) placed this genus in the Fragilariaceae but it seems most unlikely that it can remain there. On valve structure there are similarities to Papiliocellulus but these we regard as superficial due simply to the extremely slight silicification. Scale-like cingula are rare in pennate genera (though there are scales at the apices of Rhabdonema). From habitat considerations and structure, it is more likely that Subsilicea is an unusual centric genus perhaps in, or close to, the Bellerocheaceae.
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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.
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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 October 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024
