Asterolampra Ehrenberg, 1844

Holotype species: Asterolampra marylandica Ehrenberg

Original publication and holotype designation: Ehrenberg, C.G. (1844). Mittheilung über 2 neue Lager von Gebirgsmassen aus Infusorien als Meeres-Absatz in Nord-Amerika und eine Vergleichung derselben mit den organischen Kreide-Gebilden in Europa und Afrik. Bericht über die zur Bekanntmachung Geeigneten Verhandlungen der Königl. Preuss. Akademie Der Wissenschaften zu Berlin 1844: 57-97.

Description: Cells discoid, solitary. Plastids reported as numerous discoid bodies. A marine, planktonic genus of about 30 species; mainly tropical. Valves watch-glass (saucer-) shaped, without a distinct valve mantle but with a radiating system of raised rays (Gombos, 1980) which expand to touch each other in the centre (modern species) or stop short of the centre, which is then areolate (fossil species). The elevations are unperforate. At the outer ends of the rays there is a fine membrane which is usually removed by the cleaning procedure, leaving an aperture (ray hole). Immediately below this on the outer rim is the opening of a rimoportula. Between the rays the valve is areolate, each areola being loculate and opening to the outside by simple pores which form a system of obliquely crossing rows. The areolae usually appear to open internally by simple foramina but we have seen specimens with an inner 'closing' membrane (cf Actinocyclus). Internally the rays are seen to be the plain bases of open chambers the walls of which rise to the centre and sometimes curve over to form a partial roofing. It is the walls of these chambers which form the sets of radiating curved lines seen in the light microscope. A kidney-shaped rimoportula lies almost flat on the valve at the outer end of each internal chamber. Adjacent to the chambers the foramina of the areolae are elongate, giving a 'ribbed' appearance. The two valves of any one cell are displaced half a sector relative to one another, so that the cell viewed from above has the radiating elevations alternating and not superimposed. Copulae not investigated.

The most recent alteration to this page was made on 2017-01-27 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

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: 1-119, 39 plates.

Comments: Asterolampra rarely occurs in large populations and could only be confused with Asteromphalus' this, however, always has one ray narrower than the others and is thus not symmetrical. The use of the term 'pseudonodulus' for the 'ray hole' (Fryxell & Hasle, 1974) may be acceptable, though Simonsen (1975) disagrees. Its structure is similar to that in Actinocyclus (where, however, there is only a single pseudonodule). The fossil genera Discodiscus, Bergenia and Rylandsia are also characterised by rays (see Gombos, 1980, for details).

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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.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 27 January 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 27 September 2022

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