Holotype species: Craspedodiscus elegans Ehrenberg
Original publication and holotype designation: Ehrenberg, C.G. (1844). Untersuchungen über die kleinsten lebensformen im quellenlande des Euphrats und Araxes, so wie über eine an neuen formen sehr reiche marine tripelbildung von den Bermuda-Inseln. Ber. Verh. K. preuss. Akad. Wiss 1844: 253-275, 1 pl.
Taxonomic status: currently recognized as a distinct genus.
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.
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: A small centric genus of 14 species (VanLandingham, 1969), all fossil. Cells probably discoid (girdle view not seen). Presumably marine in distribution and by analogy with modern genera, planktonic. Valves circular, concentrically waved. Small areolae at centre becoming larger towards the periphery, arranged in eccentric intersecting whorls. Valve mantle shallow, with smaller areolae and a ring of small pores through the framework, which are probably the external openings of rimoportulae. Framework between the areolae massive with small external warts which are possibly the anchoring points of an outer siliceous meshwork, fragments of which are still present on the valve mantle of some cells. One areola possibly still has a velum in it - if this is real then it is of the cribrate type; the structure of the areolae would then be very similar to that in Coscinodiscus. Internally, repeating the external pattern, there are small central foramina, larger peripheral foramina and smaller mantle ones. A small plain area is present centrally on some valves and not others (therefore slightly heterovalvar?). Small triangular openings can be seen along the mantle internally, probably representing the eroded stalks of a ring of rimoportulae. Copulae not seen.The most recent alteration to this page was made on 20 Oct 2011 by M.D. Guiry.
Comments: The genus needs considerable re-investigation. Superficially it resembles Coscinodiscus, but this genus is itself in need of revision, and is indeed being split up (cf. Stellarima, Azpeitia, etc.). Hence for the moment we retain it.
Numbers of names and species: There are 34 species names in the database at present, as well as 1 infraspecific names. Of the species names, 5 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):
Click here to also show infraspecific names in the list below.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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: 23 April 2002 by M.D. Guiry
Verified by: 20 October 2011 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44374
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 10 December 2018.