Holotype species: Asteromphalus darwinii Ehrenberg
Original publication: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.
Type designated in Boyer, C.S. (1927). Synopsis of North American Diatomaceae. Part I - Coscinodiscatae, Rhizosolenatae, Biddulphiatae, Fragilariatae. Proceedings of the Academy of Natural Sciences of Philadelphia 78(Suppl.): 1-228.
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 discoid to slightly pear-shaped, rarely naviculoid, undulate in girdle view. Plastids reported as numerous discoid bodies. Marine, planktonic in warm waters but never occurring in large quantity: about 35 species. Valves shaped like watch-glasses, without a distinct valve mantle; some species slightly extended along one radius to give an obovate form. The valve has very distinctive plain rays (see Gombos, 1980, for terminology) alternating with areolate areas. The broad inner parts of the plain sectors abut at the centre or off-centre on the valve face; one ray differs from the others (the median ray of Greville, 1860) having a thinner distal section and forming a focus from which the others radiate. At the marginal (outer) end of each ray is a thin plate which is usually lost leaving a large aperture (ray hole); below this is a smaller opening, representing the external aperture of a rimoportula. This is absent on the median ray but here the thin plate is missing, the outer part of the process is morphologically different and the rimoportula must open into the ray itself for a process can be seen on the inside. The rays are long chambers opening internally by ray slits which taper towards the margin. The valve edge is plain usually with a notch offset from the end of the thin ray. The areolae are loculate. Externally their apertures are variable, though basically cribrate. Internally they have simple foramina. Flattened kidney-shaped rimoportulae occur marginally, opposite the ends of the ray slits; the rimoportula opposite the narrow ray slit is often larger. In some species small rimoportulae also occur near the central plain area. Copulae not investigated.The most recent alteration to this page was made on 7 Dec 2015 by M.D. Guiry.
Comments: Scott & Thomas (2005: 13) record this genus as being a member of the Order Centrales. This genus and Asterolampra are clearly closely related and both are found in tropical oceans. The rare 'naviculoid' forms were described by Kolbe (1955) as Liriogramma but are only boat-shaped species of Asteromphalus - they occur in the Gulf of California (Round, unpublished observation).
Numbers of names and species: There are 86 species names in the database at present, as well as 21 infraspecific names. Of the species names, 28 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.
Scott, F.J. & Thomas, D.P. (2005). Diatoms. In: Antarctic marine protists. (Scott, F.J. & Marchant, H.J. Eds), pp. 13-201. Canberra & Hobart: Australian Biological Resources Study; Australian Antarctic Division.
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: 07 December 2015 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44355
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 16 February 2020.