Biddulphiopsis Stosch & R.Simonsen, 1984
Holotype species: Biddulphiopsis titiana (Grunow) Stosch & Simonsen
Original publication and holotype designation: Stosch, H.A. von & Simonsen, R. (1984). Biddulphiopsis, a new genus of the Biddulphiaceae. Bacillaria 7: 9–36.
Description: Cells rectangular with rounded corners in girdle view; forming chains which may branch to form small colonies, and which are attached to substrata (usually other algae). Small plate-like plastids occur in the peripheral cytoplasm and in conspicuous strands radiating from a prominent central nucleus. A widespread marine genus of two species, B. titiana and B. membranacea, which were formerly placed in Biddulphia (see the detailed account of von Stosch & Simonsen, 1984). Valve outline oval to subcircular with deep vertical mantles. In girdle view the valve faces may be slightly convex; their centres may be slightly vaulted and notched towards the margins. Areolae scattered in a central elongate field, becoming organised outside this into uniseriate, radial rows and then even more precisely aligned down the mantles; occluded by rotae. Scattered pores also occur. Apices differentiated into areas of smaller pores forming rather indistinct pseudocelli. The mantle edge is extended inwards slightly to form a pseudoseptum, which is especially prominent at the apices. A row of rimoportulae occurs adjacent to the pseudocelli, sometimes forming an irregular ring around it. Internally the rimoportulae are shortly stalked, the slits not being aligned in any way. The cingulum consists of four closed copulae. The valvocopula has a narrow septum which fits over the valve pseudoseptum, while its abvalvar edge is extended at the apices forming 'false antiligulae' (von Stosch & Simonsen, 1984); the next copula is moulded to fit against this edge. The advalvar edges of the copulae have short, thin projections Ifimbriae) with a few interspersed pores, internal to which is a plain area. The areolae run in rows down the copulae and have single pegged rotae or multiple pegged, elongate rotae.
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: The genus is distinguished from Biddulphia sensu stricto by the arrangement of the rimoportulae around the ill-defined pseudocelli, the lack of distinct apical elevations and the unusual form of the copulae. Von Stosch & Simonsen discuss these points in more detail and provide excellent illustrations.
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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=45180
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 04 December 2024
