Pentasters

A small number of dinoflagellates contain an internal skeleton. One of the best known species is perhaps Actiniscus pentasterias, in which each cell contains a pair of siliceous five-armed stars surrounding the nucleus. This species was originally described by Ehrenberg.[1] Although the description is incomplete and without illustrations, Ehrenberg described the skeletal elements but mentioned that the living cell was colorless and non-motile. Ehrenberg subsequently diagrammed the silicified skeletal elements (pentasters) from geological deposits in various parts of the world.[2]These can be found as microfossils. Pentasters were studied from the Cenozoic South Pacific by Dumitrică http://deepseadrilling.org/21/volume/dsdp21_25.pdf [3] Tappan [4] gave a survey of dinoflagellates with internal skeletons. This included the first detailed description of the pentasters in Actiniscus pentasterias, based on scanning electron microscopy.

The ultrastructure of Actiniscus pentasterias was investigated.[5]

References

  1. Ehrenberg, C. G. 1841. Uber noch jetzt zahlreich lebende Tierarten der Kreidebildung und den Organismus der Polythalamien. Abh. K. Akad. Wiss. Berlin 1839:81-174, pls. 1-4.
  2. Ehrenberg, C. G. 1854. Mikrogeologie das Erden und Feslen schaffende Wirken desunsichtbaren kleinen selbstandigen Lebens auf der Erde. Leopold Voss, Leipzig, 374 pp., pls. 1-40.
  3. Dumitrică, P., 1973: Cenozoic endoskeletal dinoflagellates in southwestern Pacific sediments cored during Leg 21 of the DSDP. In: Burns, R.E. et al., Deep Sea Drilling Project, Washington, Initial Reports, v.21, p.819-835, pl.1-5.
  4. Tappan, H. 1980. The Paleobiology of Plant Protists. Freeman and Company, San Francisco, 1028 pp.
  5. Hansen, G. 1993. LIGHT AND ELECTRON MICROSCOPICAL OBSERVATIONS OF THE DINOFLAGELLATE ACTINISCUS PENTASTERIAS (DINOPHYCEAE) J. Phycol. 29, 486-499 (1 993)
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