Sökning: "Early Cambrian"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden Early Cambrian.

  1. 1. The Cambrian lophotrochozoans of the Transantarctic Mountains, Antarctica

    Författare :Lewis Bassett-Butt; Lars Holmer; Glenn Brock; Christian Skovsted; Jan Ove Ebbestad; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Brachiopoda; Dailyatia; Cambrian; Drumian; Middle Cambrian; Early Cambrian; Antarctica; tommotiid; camenellan; palaeobiology; small shelly fossils; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : The origin of many lophotrochozoan groups can be traced to “small shelly fossil” (SSF) faunas of the Early Cambrian. Antarctica is a key region of study, due to the continent’s known close geographical proximity to well-studied Australian and Indian basins in in the Cambrian. LÄS MER

  3. 2. The Early Cambrian Fauna of North-East Greenland

    Författare :Christian B. Skovsted; John S. Peel; Lars E. Holmer; Gerd Geyer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Early Cambrian; Dyeran; Botoman; Biostratigraphy; Palaeogeography; Small Shelly Fossils; Brachiopoda; Mollusca; Hyolitha; Trilobita; Geovetenskap; Earth sciences; Geovetenskap;

    Sammanfattning : Small shelly fossils are common in sediments of Early Cambrian age and include the earliest common representatives of metazoan animals with mineralized hard parts. The group includes fossils of very different morphology, composition and ultrastructure. LÄS MER

  4. 3. Early Cambrian Problematic Lophotrochozoans and Dilemmas of Scleritome Reconstructions

    Författare :Cecilia M Larsson; Lars E Holmer; Christian B Skovsted; Anette E S Högström; John S Peel; Glenn A Brock; Michael J Vendrasco; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Problematica; scleritome; Trachyplax; tommotiid; Cambrian; South Australia; North Greenland; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : The emergence and radiation of metazoan body plans around the Precambrian/Cambrian boundary, some 500-600 million years ago, seems to be concordant with the appearance and diversification of preservable hard parts. Several Precambrian soft-bodied, multicellular organisms most likely represent stem-group bilaterians, but their fossil record is rather sparse. LÄS MER

  5. 4. Decoding the fossil record of early lophophorates : Systematics and phylogeny of problematic Cambrian Lophotrochozoa

    Författare :Aodhán D. Butler; Michael Streng; Lars E. Holmer; Russell Garwood; Maggie Cusack; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Brachiopoda; Chengjiang; Lagerstätte; Cambrian Explosion; palaeobiology; stem-group; entoproct; phoronid; tommotiid; exceptional preservation; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : The evolutionary origins of animal phyla are intimately linked with the Cambrian explosion, a period of radical ecological and evolutionary innovation that begins approximately 540 Mya and continues for some 20 million years, during which most major animal groups appear. Lophotrochozoa, a major group of protostome animals that includes molluscs, annelids and brachiopods, represent a significant component of the oldest known fossil records of biomineralised animals, as disclosed by the enigmatic ‘small shelly fossil’ faunas of the early Cambrian. LÄS MER

  7. 5. Neoproterozoic-Early Cambrian organic-walled microfossils : Ultrastructural and biogeochemical search for their affinities

    Författare :Nina M. Talyzina; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Geovetenskap; Earth sciences; Geovetenskap; Historical Geology and Paleontology; historisk geologi och paleontologi;

    Sammanfattning : The Neoproterozoic-Cambrian transition is marked by conspicuous radiation of skeletal fauna comparable to modern invertebrates. Phylogenetic relationships of living organisms, based on their genetic and ultrastructural complexity, suggest that most prokaryotic and protistan organisms should have evolved by the time of origination of coelomate organisms. LÄS MER