NEW MULTICELLULAR MICROFOSSIL EUKARYOTES FROM THE CA. 950–820-MILLION-YEAR-OLD VETERANEN GROUP OF SVALBARD

The Neoproterozoic diversification of complex eukaryotes marks a pivotal turning point in the history of life on the Earth. Molecular clocks predict the emergence of major eukaryotic clades (e.g., red and green algae) by ca. 1000 Ma. However, it is difficult to test this hypothesis due to the rarity of early eukaryote fossils with sufficient morphological characters to be allied to modern groups. Here we report new multicellular microfossils from mud- and siltstone facies of the ca. 950–820 Ma Veteranen Group of Svalbard. The succession is ca. 4.5 km thick and records deposition largely in marginal marine environments that may have been relatively nutrient-rich. Microfossil data from samples collected at Faksevågen, Spitsbergen, and across multiple sites on Nordaustlandet and Lågøya, indicate a community with a modest diversity of eukaryotes. This contrasts with younger deposits from Svalbard, like the ca. 800 Ma Svanbergfjellet Formation, which are among the most diverse Neoproterozoic assemblages worldwide. However, preservation quality in the Veteranen Group is high and three new exceptionally preserved multicellular taxa are recorded. These taxa may have affinities with brown and red algae, and perhaps fungi. If so, this assemblage substantially increases the number of taxa older than 600 Ma that can be used to date the emergence of key groups of eukaryotes, however convergent evolution by now extinct clades is also possible. Regardless, these new fossils indicate that multicellular eukaryotes had evolved morphologies comparable to those of eukaryotes today by the mid-Tonian Period.