Acritarchs of the Precambrian in mobile zones

Timofeyev, B V; Cirot, Georges; Faure-Muret, Anne

doi:10.1016/0012-8252(80)90045-8

Cited by 9 publications

(3 citation statements)

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“…Charnwood Forest yields even less evidence for microfossil preservation (Peat, 1994), despite promising early reports (Tymofeyev et al, 1980). Investigations in the marginal-marine deposits of the Long Mynd, Shropshire, have been more rewarding, yielding spheroidal and filamentous forms preserved in at least three taphonomic modes (Peat, 1984;Callow and Brasier, 2009b).…”

Section: Microfossilsmentioning

confidence: 95%

Remarkable insights into the paleoecology of the Avalonian Ediacaran macrobiota

2015

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Ediacaran macrofossils from the Avalon Terrane (primarily eastern Newfoundland and the central U.K.) record some of the earliest large and complex multicellular organisms on Earth.Perhaps the greatest unknown regarding these fossils is their relevance to the early evolutionary history of the Kingdom Animalia. In recent years, new data and discoveries have revealed insights into Ediacaran paleobiology, taxonomic relationships, paleoecology and taphonomy, significantly refining our understanding of Avalonian ecosystems. Here, we summarise recent observational and quantitative studies, and their bearing on the current understanding of Avalonian benthic marine ecosystems. A review of existing knowledge of the biological composition of Avalonian marine assemblages demonstrates that they recorddensely-populated ecosystems inhabited by a diverse range of organisms, likely representing multiple biological Kingdoms. Appreciation of this diversity, and of the complexities it introduces to paleoecological studies, is vital when considering the relationship between macroevolution and contemporaneous climatic, tectonic and geochemical events. We then summarise current understanding of Avalonian paleoecology. Studies into locomotion, reproduction, feeding strategies, and community structure and succession reveal that these ecosystems were considerably different to Phanerozoic settings. Furthermore, we suggest that Avalonian ecosystems witnessed the appearance of novel nutrient sources, offering new opportunities and niches for benthic organisms. The suggestion that the numerically dominant rangeomorphs were osmotrophic is reviewed and appraised in light of geochemical, morphological, and biological information. Finally, the use of modern ecological metrics in the study of Ediacaran fossil assemblages is assessed. Concerns regarding the interpretation of paleoecological data are outlined in light of current taphonomic and sedimentological understanding, and these cast doubt on previous suggestions that the Avalonian assemblages were largely composed of metazoans. Nevertheless, we emphasise that if treated with necessary caution, paleoecological data can play a significant role in assisting efforts to determine the biological affinities of late Ediacaran macroscopic organisms.

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Section: Microfossilsmentioning

confidence: 95%

Remarkable insights into the paleoecology of the Avalonian Ediacaran macrobiota

2015

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“…Microfossils from the Longmyndian were first reported by Timofeyev et al (1980), and Peat (1984) described carbonized, mat-forming, ribbon-like and sphaeromorph microfossils from petrographic thin sections, which were compared with prokaryotes, eukaryotes and even questionably with metazoans. Here, we report on a fresh study of Salter's historical material, supplemented by new specimens from the Burway Formation at Ashes Hollow and the Lightspout Formation in Carding Mill Valley, Shropshire (see Greig et al 1968), focusing upon the evidence for exceptional fossil preservation on a microscopic scale.…”

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confidence: 98%

A solution to Darwin's dilemma of 1859: exceptional preservation in Salter's material from the late Ediacaran Longmyndian Supergroup, England

Callow

Brasier

2009

JGS

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Study of historical and fresh collections from the Longmyndian Supergroup sheds new light on Ediacaran microbial communities and taphonomy. First reported by Salter in 1856, and noted by Darwin in the Origin of Species in 1859, a range of macroscopic bedding plane markings are already well known from the Longmyndian supergroup. Here we report filamentous and sphaeromorph microfossils, variously preserved as carbonaceous films, by aluminosilicate permineralization and as bedding plane impressions. This supports a long-suspected link between wrinkle markings and microbes, and draws further attention to our hypothesis for a taphonomic bias towards high-quality soft tissue preservation in the Ediacaran Period.

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“…Assemblages of organic-walled microfossils have recently been reported from the Blackbrook Formation and Maplewell Group of the Charnian, and the Buxton Rock (?) of the Longmyndian (Choubert & Faure-Muret, 1980, p. 190-2;Timofeyev et al, 1980). The microfossils were described only from macerations, and exact sampling sites were not recorded.…”

Section: Longmyndian and Charnianmentioning

confidence: 99%

Comments on some of Britain’s oldest microfossils

Peat¹

1984

J. Micropalaeontol.

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Abstract. A critical re-appraisal of some reports of British Precambrian microfossils illustrates potential pitfalls in describing Precambrian microbiotas. The Ceinwen and Llanddwyn Spilitic Formation of the Gwna Group contains convincing filamentous microfossils, but a report of acanthomorph arcitarchs has not yet been confirmed. Although the Diabaig Formation of the Torridon Group is known to be abundantly fossiliferous, a report based on S.E.M. without thin section control is rejected. Chert pebbles from the Applecross Formation of the Torridon Group do not contain convincing microfossils. They are contaminated by fungi and contain abiogenic structures which resemble cells and tissues. Reports of diagnostic Middle Riphean microfossils from the Blackbrook Formation and the Maplewell Group of the Charnian and the Buxton Rock of the Longmyndian await confirmation.

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Acritarchs of the Precambrian in mobile zones

Cited by 9 publications

References 1 publication

Remarkable insights into the paleoecology of the Avalonian Ediacaran macrobiota

Remarkable insights into the paleoecology of the Avalonian Ediacaran macrobiota

A solution to Darwin's dilemma of 1859: exceptional preservation in Salter's material from the late Ediacaran Longmyndian Supergroup, England

Comments on some of Britain’s oldest microfossils

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