Stellarima Hasle & P.A.Sims, 1986

Holotype species: Stellarima microtrias (Ehrenberg) G.R.Hasle & P.A.Sims

Original publication and holotype designation: Hasle, G.R. & Sims, P.A. (1986). The diatom genera Stellarima and Symbolophora with comments on the genus Actinoptychus. British Phycological Journal 21: 97-114.

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Description: Cells discoid, solitary. Plastid morphology unknown. Stellarima species have usually been placed in Coscinodiscus. Nikolaev (1983) recognised that they do not belong there and resurrected Symbolophora Ehrenberg, placing in it S. microtrias as the type, together with five other species, all previously in Coscinodiscus; he also created the new family Symbolophoraceae. However, the type of Symbolophora is in fact an Actinoptychus (Cymatogonia) and therefore the name Symbolophora cannot be used for these species; hence Hasle & Sims (1986) have erected the genus Stellarima. A marine planktonic genus - our material came from the Antarctic, like most material studied by others, but also some samples were from the coast of South Africa. Valves circular, convex, without a distinct valve mantle. Striae uniseriate, radial, some reaching the centre, others shorter; fasciculate in resting spores (Syvertsen, 1985). Areolae loculate; outer openings simple or with cribra; some scattered cribra have one central pore and are more regular than the others; internal apertures with domed closing plates. Rimoportulae central, arranged in a ring in the centre of the valve; 1-15 have been observed. Externally the rimoportulae have slit-like openings; internally they are elongate and raised, their lips being orientated radially. No other portules present. Copulae not observed.

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: 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: This genus differs from Coscinodiscus in having no marginal rimoportulae but only central radiate rimoportulae and in having internal closing plates to the areolae. It is therefore more akin to genera such as Actinocyclus. Resting spores and comments on palaeoceanographic and evolutionary problems in this genus are discussed by Sims & Hasle (1987).

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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. 07 December 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 10 December 2023

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