Brockmanniella Hasle, Stosch & Syvertsen, 1983
Holotype species: Brockmanniella brockmannii (Hustedt) 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.
Taxonomic status: currently recognized as a distinct genus.
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: -119, 39 pls.
Description: Cells attached to form long chains which may be twisted. Cells rectangular (oval in small cells) with slight apical and central expansions of the valve. Sibling valves touch at the centres and may also be in contact at the apices. One plastid, constricted in the centre and lying along one side of the cell. Common on the sediments of the North Sea and also appearing in the plankton. Probably widespread: our samples were cultures from around the British Isles but we have also found it off Florida. Valves linear, lanceolate to oval with prominent offset ocelluli on apical elevations. A central raised fascia is devoid of areolae, except along the margin. There is no obvious sternum. The areolae are in transverse rows and are closed towards the outside by delicate vela. A single row of spines occurs around the margin just above the outer ring of areolae and a few spines may occur scattered on the central area and elsewhere. The valve surface may be finely granular. Pili are absent. Ocelluli occur diagonally opposite one another and in a clockwise position; they have a slight rim. An offset process (rimoportula?) occurs on one valve only. Cingulum of numerous simple, slightly porous copulae, the last one having a row of granules close to the abvalvar edge (Hasle et al., 1983).The most recent alteration to this page was made on 9 Dec 2015 by M.D. Guiry.
Comments: This genus was erected for a species previously placed in Plagiogramma (P. brockmannii), based on its lack of pili and pseudosepta. As in other related genera the initial cells differ somewhat, e.g. they lack spines. We have not observed the concave and convex thecae recorded by Hasle et al. in post-auxospore material. The genus is quite close to Cymatosira belgica and to Plagiogrammopsis vanheirckii but we agree fully with Hasle et al. that it is preferable to maintain separate genera when there is a distinction involving such prominent features as pili and pseudosepta.
Numbers of names and species: There are 2 species names in the database at present, of which 2 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):
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Verification of data
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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.
Created: 27 April 2003 by Mairead Murphy
Verified by: 09 December 2015 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=46450
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 23 February 2020.