Briggera R.Ross & P.A.Sims, 1985
Holotype species: Briggera ornithocephala (Greville) R.Ross & P.A.Sims
Original publication and holotype designation: Ross, R. & Sims, P.A. (1985). Some genera of the Biddulphiaceae (diatoms) with interlocking linking spines. Bulletin of the British Museum (Natural History) 13: 277-381.
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 'hemiauloid' thus forming colonies linked by apical elevations. The genus is fossil and has been separated from Hemiaulus by Ross & Sims (1985). Found in marine sediments of upper Cretaceous to Lower Miocene age. Valves elliptical, undulate with the two apical swellings extended into massive elevations ending in swollen apices. Valve surface areolate with simple but deep pores penetrating the silica; often with scattered spines. The central region of the valve face is separated from the ends by clear transverse bands of silica. The valve mantle is plain or slightly areolate and raised into a rim at the valve face/mantle junction. The elevations have a porous area forming a pseudocellus on each apical swelling, facing outwards. The inward face of the swelling is produced into a series of ridges or spines (5 or fewer) which interlock with those on the adjacent valve. Internally the only conspicuous features are the two ridges of plain silica traversing the valves. Rimoportulae absent or 1-5 scattered near the centre of the valve; each has a short external tube and an internal slit (rimoportulae were not present on the material we use for illustration). We have not seen the cingulum but it is reported to consist of 3-4 (or more) open copulae (Ross & Sims, 1985).
The most recent alteration to this page was made on 2015-12-07 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: Ross, Sims & Hasle (1977) considered the genus Hemiaulus in detail and at that time species such as capitatus, includens and haitensis were included and figured; these should now be placed in Briggera. Ross & Sims (1985) have dealt with the new genus in a most comprehensive manner, together with Strelnikovia, Keratophora, Thaumatonema and Dicladiopsis. Hemiaulus differs from Briggera principally in having much more slender elevations, which have apical spines that do not interlock and much smaller or almost non0existent ocelli. In addition, the valve of Hemiaulus does not have such clear transverse plain areas on the valve face and the areolae are more closely spaced.
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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=46628
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 07 December 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 28 November 2024
