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The life cycle and developmental phases of Cambrian-Ordovician organic-walled microfossils from Kolguev Island, Arctic Russia.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
2016 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Livscykel och utvecklingsfaser hos kambrisk–ordoviciska organiska mikrofossil från Kolguev, arktiska Ryssland (Swedish)
Abstract [en]

Light microscopy studies of collections of late Cambrian/Early Ordovician organic-walled microfossils, informally called acritarchs, provide the observations on phenotypic traits that are comparable to Modern microalgae and make possible recognition of various developmental stages in their complex life cycle. The exceptionally preserved Saharidia fragilis microfossils show the internal body within the vesicle and the formation of the fringe and pylome, the opening for releasing of the daughter cells from the phycoma-like cyst. All the reproductive stages are distinguished and the hypothetical reconstruction of the complex life cycle is proposed. Various morphotypes are recognized to be a part of the class Prasinophyceae and some microfossils of the genus Leiosphaeridia are thought to represent the develop-mental stage of Saharidia fragilis life cycle. The morphological similarity suggests that those micro-fossils from the Cambrian-Ordovician transitional time interval are the ancestral representatives and early lineages of the Modern class Prasinophyceae.

Abstract [sv]

Alger är idag viktiga producenter av fritt syre i atmosfären. I denna avhandling presenteras nya studier av encelliga organiska mikrofossil från den ryska ön Kolguev. Fossilens form och struktur (där många visar på en karaktäristisk rund öppning, så kallad pylome) ger en grund för att rekonstruera en komplex livscykel hos vissa av dessa kambrisk-ordoviciska taxa och tolka dem som alger. Studier med hjälp av ljusmikroskop utfördes i syfte att fastställa mikrofossilens funktionsmorfologi och fenotypiska drag. Dessa studier är viktiga för att klargöra biologiska släktskap och livscykeln av de studerade arterna.

Place, publisher, year, edition, pages
2016. , 59 p.
Examensarbete vid Institutionen för geovetenskaper, ISSN 1650-6553 ; 350
Keyword [en]
Saharidia fragilis, Prasinophyceae algae, life cycle, acritarchs
Keyword [sv]
Saharidia fragilis, Prasinophyceae, livscykel, acritarch
National Category
Earth and Related Environmental Sciences
URN: urn:nbn:se:uu:diva-281611OAI: oai:DiVA.org:uu-281611DiVA: diva2:914711
Educational program
Master Programme in Earth Science
2015-09-14, Norrland 1, Geocentrum, Villavägen 16, Uppsala, 15:00 (English)
Available from: 2016-03-25 Created: 2016-03-24 Last updated: 2016-03-25Bibliographically approved

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