Actinoptychus Ehrenberg, 1843
Lectotype species: Actinoptychus senarius (Ehrenberg) Ehrenberg
Original publication: Ehrenberg, C.G. (1843). Verbreitung und Einfluss des mikroskopischen Lebens in Süd- und Nord-Amerika. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin 1841: 291-445 + [1, Berichtigungen], + 4 pls.
Request PDFType 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.
Description: Cells discoid, solitary. Very common in neritic collections, probably mainly a component of the assemblage lying loose or attached to other algae on coastal sediments. Plastids several, irregular plates. Many fossil species. Valves sectored (6 in the common A. senarius [= A. undulatus] but up to 20 others) so that alternate sectors are elevated or depressed. Central area plain or granulate. Areolae in radiate striae, opening by simple pores to the outside but over much of the surface the silica is corrugated or pitted, delimiting groups of areolae. Internally, uneroded areolae are closed by domed vela. External tubes of rimoportulae prominent, usually located at distal points on radii of elevated sectors. Depressions (termed pseudopores by Andrews, 1979) occur at the corresponding position on the depressed sectors. The internal openings of the rimoportulae tend to lie at right angles to the valve margin and are either straight or curved. Valve framework bullulate. Margin of valve face often produced into a thickened rim or marked with special ornamentation below which the distinctively patterned valve mantle extends. The valve mantle often has spines, wart-like outgrowths, siliceous ridges, etc., and the edge is produced into a smooth flange. Copulae plain, split and wide.
The most recent alteration to this page was made on 2024-10-01 by G.M. Guiry.Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Fourtanier, E.J. & Kociolek, J.P. (2009). Catalogue of diatom names: Part II: Abas through Bruniopsis. Occasional Papers of the California Academy of Sciences 156(II): 1-231, 2 figs, 1 table.
Comments: Andrews (1979) shows that the arrangement of rimoportulae can vary, with more than one in each raised sector, and that they can also occur on the edge of the depressed sectors, at least in A. heliopelta. A genus with numerous species and varieties (VanLandingham records 150 possible valid species) many of which require re-investigation. Its ecology also requires further study. The primary valves were formerly described as the genus Debya Pantoscek.
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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=43721
Citing AlgaeBase
Cite this record as:
G.M. Guiry in Guiry, M.D. & Guiry, G.M. 01 October 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 24 November 2024
