uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Ultrastructure of cell walls in ancient microfossils as a proxy to their biological affinities
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
2009 (English)In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 173, no 1-4, 27-38 p.Article, review/survey (Refereed) Published
Abstract [en]

Bacteria and protoctists dominated the biosphere in the Archean and Proterozoic, their affinities being deduced by studies of their comparative morphology, palaeoecology, biogeochemistry, and wall ultrastructure. However, exact phylogenetic relationships are uncertain for most such microfossils. Because of the limitations imposed by the simple morphology and small dimensions of such microorganisms and their little known biochemistry, new techniques in microscopy, tomography and spectroscopy are applied to examine individual microfossils at the highest attainable spatial resolution. TEM/SEM studies of the wall ultrastructure of sphaero- and acanthomorphic acritarchs have revealed complex, single to multilayered walls, having a unique texture in sub-layers and an occasionally preserved trilaminar sheath structure (TLS) of the external layer. A variety of optical characteristics, the electron density and texture of fabrics of discrete layers, and the properties of biopolymers may indicate the polyphyletic affiliations of such microfossils and/or the preservation of various stages (vegetative, resting) in their life cycle. Primarily, wall ultrastructure allows discrimination between fossilized prokaryotic and eukaryotic cells. Composite wall ultrastructure provides evidence that some Proterozoic and Cambrian leiosphaerids are of algal affinities (but not, per se, that they are referable to "Leiosphaeridia"). Certain Cambrian specimens represent chlorophyceaens, having the multilayered composite wall with TLS structure known from vegetative and resting cells in modern genera of the Chlorococcales and Volvocales. The wall ultrastructure of the studied Cambrian and Proterozoic acanthomorphs resembles the resting cysts of green microalgae, but there is no evidence to suggest a close relationship of these taxa, to dinoflagellates. It is apparent that although there is no single and direct method to recognize the precise phylogenetic relations of such microfossils, ultrastructural studies of their preserved cell walls and encompassing sheaths, combined with biochemical analyses and other advanced methods, may further elucidate their affinities to the modern biota.

Place, publisher, year, edition, pages
2009. Vol. 173, no 1-4, 27-38 p.
Keyword [en]
Ultrastructure, Cell wall, Acritarcha, Microfossils, Affinities, Ediacaran
National Category
Earth and Related Environmental Sciences
URN: urn:nbn:se:uu:diva-142198DOI: 10.1016/j.precamres.2009.02.006ISI: 000269297400005OAI: oai:DiVA.org:uu-142198DiVA: diva2:387156
Neoproterozoic microbial diversification - a prelude to the Proterozoic world
Swedish Research Council
Available from: 2011-01-13 Created: 2011-01-13 Last updated: 2014-12-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Moczydlowska, MalgorzataWillman, Sebastian
By organisation
In the same journal
Precambrian Research
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 117 hits
ReferencesLink to record
Permanent link

Direct link