Butterfield, N. J. (2004) A vaucheriacean alga from the middle Neoproterozoic of Spitsbergen: implications for the evolution of Proterozoic eukaryotes and the Cambrian explosion. Paleobiology, 30. pp. 231-252. ISSN ISSN: 0094-8373
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Abstract
A morphologically diverse assemblage of organic-walled fossils from the middle Neo- proterozoic Svanbergfjellet Formation, Spitsbergen, is identified as a monospecific assemblage rep- resenting the Gongrosira-phase of a vaucheriacean xanthophyte alga. As such, it provides a range of additional criteria with which to identify fossil vaucheriaceans and confirms the identification of Palaeovaucheria in the Mesoproterozoic Lakhanda Formation. Pronounced taxonomic inflation, through the practice of form-taxonomy, suggests that overall estimates of eukaryotic diversity in the Proterozoic need to be adjusted downward. Combined with positive evidence for low levels of speciation and extended stasis, pre-Cambrian eukaryotes are seen to evolve at a fundamentally lower rate than their Phanerozoic counterparts. This slower turnover accounts for the "delayed" appearance of animals without appeal to external triggers or constraints. The Cambrian acceler- ation of evolutionary rates was a direct consequence of newly introduced animals, whereas the much slower overall rates of the Proterozoic imply an absence of earlier metazoans.
Item Type: | Article |
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Uncontrolled Keywords: | 2004 AREP 2004 P IA44A IA46 |
Subjects: | 04 - Palaeobiology |
Divisions: | 04 - Palaeobiology |
Journal or Publication Title: | Paleobiology |
Volume: | 30 |
Page Range: | pp. 231-252 |
Depositing User: | Sarah Humbert |
Date Deposited: | 29 Jun 2015 17:12 |
Last Modified: | 29 Jun 2015 17:17 |
URI: | http://eprints.esc.cam.ac.uk/id/eprint/3345 |
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