Lepidodiscus Witt, 1886
Holotype species: Lepidodiscus elegans Witt
Original publication and holotype designation: Witt, O.N. (1886 '1885'). Ueber den Polierschiefer von Archangelsk-Kurojedowo im Gouv. Simbirsk. Verhandlungen der Russisch-kaiserlichen Mineralogischen Gesellschaft zu St. Petersburg, Series II 22: 137-177, pls. VI-XII.
Fossil: This is a genus of fossil species, or a genus with a fossil type species, or a genus the type species of which was originally described as a fossil.
Description: Cells probably discoid, but only valves seen. A small genus of fossils (7 spp. according to VanLandingham, 1971), most occurring in Eocene sediments of marine origin. Valves circular, with concentric undulations of the valve face and in addition a ring of prominent alternating elevations and hollows around the circumference. The system of elevations and hollows is relatively slight in our material; other species have very pronounced external ridges and furrows (P.A. Sims, personal communication) and this results in very dissilar sibling valves. Areolae in fascicles (striae) radiating from a central annulus, within which the areolae are randomly scattered; the fascicles increase in width towards the margins and then split up again in the undulate marginal region. The areolae are circular and appear to be simple passages through the massive framework of the valve. Valve mantle short and areolate; on a ridge between it and the valve face there appears to be a series of openings, each surrounded by paired flaps of silica; these are presumably the openings of the rimoportulae; a similar arrangement has been seen in several Actinoptychus species. Internally the valve surface is plain; the plain strips between the fascicles become 'buttresses' around the margin, connecting the valve face to the edge of the mantle. Within the depressions between the buttresses the rimoportulae can be seen, one per depression, their apertures orientated radially. Copulae unknown.
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: A little known genus which requires further study, especially of the valve mantle and of material with copulae attached. From these admittedly preliminary observations the genus seems close to Actinoptychus.
Verification of Data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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=46620
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 23 April 2024
