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Reproductive cyst a...
Reproductive cyst and operculum formation in the Cambrian-Ordovician galeate-plexus microfossils
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- Agić, Heda, 1989- (författare)
- Uppsala universitet,Paleobiologi,ORIGINS AND EARLY DIVERSIFICATION OF PHOTOSYNTHETIC MICROBIOTA
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- Moczydłowska, Małgorzata (författare)
- Uppsala universitet,Paleobiologi,ORIGINS AND EARLY DIVERSIFICATION OF PHOTOSYNTHETIC MICROBIOTA
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- Canfield, Donald (författare)
- University of Southern Denmark
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(creator_code:org_t)
- 2016-02-05
- 2016
- Engelska.
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 138:2, s. 278-294
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Unicellular organic-walled microfossils from the Cambrian-Ordovician transition in Estonia (ca. 490-480 million years ago) exhibit rare characters reflecting their function as reproductive algal cysts. The studied assemblages record the evolutionary history of phytoplankton in the early Paleozoic Era: novel morphologies appearing through the Cambrian and subsequently diversifying in the Ordovician. Well preserved specimens were extracted following a standard palynological method and studied by light transmitted microscopy. The galeate plexus acritarchs Caldariola, Priscogalea and Stelliferidium have revealed exceptionally preserved morphological elements and a rare structure among both fossil and extant protists – an opening with operculum (lid) in reproductive cysts, in addition to lavish vesicle ornamentation and sculpture. Analogous morphology is observed in the living dasycladalean alga Acetabularia (Chlorophyta), which possesses an intrinsic lid-forming apparatus used during organism’s reproductive stage. Based on the observations on the fossil material and studies on the Acetabularia lid-formation, we propose a model of operculum formation in the galeate plexus microorganisms. Due to strong morphological and ecological similarities between galeate fossils and dasycladalean cysts, and the antiquity of this algal order, galeates may be positioned within green algae, more specifically Dasycladales. Unique morphology of the operculum-bearing microbiota would have required a high degree of intracellular complexity for its development, suggesting that advanced intracellular machinery was present already in the early Paleozoic phytoplankton. Additionally, minute prasinophyte microfossils Reticella corrugata are reported for the first time in the Upper Cambrian strata.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geology (hsv//eng)
- NATURVETENSKAP -- Biologi -- Botanik (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Botany (hsv//eng)
Nyckelord
- acritarchs
- Baltica
- cyst-formation
- Dasycladales
- Estonia
- galeate plexus
- microfossils
- operculum
- Ordovician
- palaeobiology
- Earth Science with specialization in Historical Geology and Palaeontology
- Geovetenskap med inriktning mot historisk geologi och paleontologi
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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