Publications of Corentin Loron
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See detailPaleobiology of an Ediacaran acanthomorphic acritarch
Domino, Samuel ULiege; Loron, Corentin ULiege; Sforna, Marie-Catherine ULiege et al

Poster (2021, July)

The Ediacaran is a crucial time of changes in climatic and redox conditions, nutrient availability, and diversification of eukaryotes, including planktonic algae and the first unambiguous metazoans ... [more ▼]

The Ediacaran is a crucial time of changes in climatic and redox conditions, nutrient availability, and diversification of eukaryotes, including planktonic algae and the first unambiguous metazoans. During this period, new and highly diverse organic-walled eukaryotic microfossils appear worldwide, but their identity remains enigmatic. They are called the “Doushantuo-Pertatataka type Acanthomorphic acritarchs” (DPA). Their morphological complexity (diverse types of processes expanding from the vesicle wall) evidences their eukaryoticity. Several hypotheses for their affinity have been proposed, tentatively interpreting a few of these microfossils as eggs of metazoans [1,2] or cysts of chloroplastid green algae [2-5], but they remain ambiguous. To test these hypotheses, we present a morphological, ultrastructural and spectroscopic characterisation of one of the most emblematic DPA acritarchs, Gyalosphaeridium pulchrum. Such analytical combination has never been performed all together on a DPA taxon. The fossils come from the Munta-1 drillcore from the Tanana formation in the eastern Officer basin in Australia. Quantitative analyses [6] of microfossils through the drillcore revealed assemblages dominated by simple smooth-walled sphaeromorphs, and less abundant but very diverse and exquisitely preserved acanthomorphs, previously reported [7]. Drawing on our analyses and previous work, we discuss the possible diagnostic combinations of characters to pinpoint the clade to which the microfossils may belong. This approach, extended to more DPA taxa, will permit to constrain the appearance of eukaryotic clades in the Ediacaran and their role in the complexification of late Precambrian ecosystems. It will also provide guidelines for future identification of similarly enigmatic microfossils, frequent in Precambrian and Paleozoic strata. [1] Cohen, Knoll & Kodner (2009), Proceedings of the National Academy of Sciences 106, 6519–6524. [2] Willman (2009), Geobiology 7, 8–20. [3] Marshall, Javaux, Knoll & Walter (2005), Precambrian Research 138, 208–224. [4] Moczydłowska & Liu (2021), Geological Magazine, doi:10.1017/S0016756820001405. [5] Willman & Moczydłowska (2007), Lethaia 40, 111–123. [6] Calers (2020), Diversification de la biosphère après un impact de météorite (Acraman, Australie) au Néoprotérozoïque, M. Sc. thesis, Université de Liège. [7] Grey (2005), Memoirs of the Association of Australasian Palaeontologists 31, 439 pp. [less ▲]

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See detailShale-hosted biota from the Dismal Lakes Group in Arctic Canada supports an early Mesoproterozoic diversification of eukaryotes
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Robert et al

in Journal of Paleontology (2021)

The Mesoproterozoic is an important era for the development of eukaryotic organisms in oceans. The earliest unambiguous eukaryotic microfossils are reported in late Paleoproterozoic shales from China and ... [more ▼]

The Mesoproterozoic is an important era for the development of eukaryotic organisms in oceans. The earliest unambiguous eukaryotic microfossils are reported in late Paleoproterozoic shales from China and Australia. During the Mesoproterozoic, eukaryotes diversified in taxonomy, metabolism, and ecology, with the advent of eukaryotic photosynthesis, osmotrophy, multicellularity, and predation. Despite these biological innovations, their fossil record is scarce before the late Mesoproterozoic. Here, we document an assemblage of organic-walled microfossils from the 1590–1270 Ma Dismal Lakes Group in Canada. The assemblage comprises 25 taxa, including 11 morphospecies identified as eukaryotes, a relatively high diversity for this period. We also report one new species, Dictyosphaera smaugi new species, and one unnamed taxon. The diversity of eukaryotic forms in this succession is comparable to slightly older assemblages from China and is higher than worldwide contemporaneous assemblages and supports the hypothesis of an earlier diversification of eukaryotes in the Mesoproterozoic. [less ▲]

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See detailNEW REPORT OF SHALE-HOSTED ORGANIC-WALLED MICROFOSSILS FROM THE EARLY MESOPROTEROZOIC DISMAL LAKES GROUP IN ARCTIC CANADA
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Robert et al

Conference (2021)

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See detailDiversity, paleobiology and ecology of Organic-walled Microfossils from the Proterozoic of Arctic Canada, and implications for early eukaryotic evolution.
Loron, Corentin ULiege

Doctoral thesis (2020)

Understanding the appearance and evolution of Life on our Planet (and elsewhere?) requires multidisciplinary approaches intersecting, notably, biology, geology, chemistry and astronomy. Studies of Earth ... [more ▼]

Understanding the appearance and evolution of Life on our Planet (and elsewhere?) requires multidisciplinary approaches intersecting, notably, biology, geology, chemistry and astronomy. Studies of Earth deep times provide insights on the early hydrosphere, atmosphere and geosphere which influenced the development of the early biosphere. Conversely, the transition from prebiotic chemistry to life and subsequent biological changes (prokaryotic then eukaryotic photosynthesis, rise of eukaryotes, appearance of crown-groups, …) also played a role in modifying our young planet. This study focuses on a fundamental period for the diversification of Life on earth, the Proterozoic, that span from 2500 to 541 Ma. The total diversity of organic-walled microfossils present in two unmetamorphosed sedimentary successions from the northwestern Canada was investigated: The Dismal Lakes Group and the lower Shaler Supergroup. These successions represent more than 700 million years of earth history (from 1600 to 900 Ma) and preserve beautiful and abundant microfossils, especially numerous taxa of eukaryotes. This thesis demonstrates that the major diversification of eukaryotes observed in the fossil record at ~800 Ma has, in fact, started earlier and was more gradual. Eukaryotes were diversified by the early Mesoproterozoic and crown groups might have already appeared by then. New and earlier evidence for eukaryovory permits to suggest that predation was probably a powerful driver of this diversity rise. By combining classical paleontological approaches with spectroscopic and ultrastructural analyses, a new candidate of crown-group eukaryote, Ourasphaira giraldae could be proposed. This microfossil, recognized as an early fungus, provides new insights into crown-group diversification in the Proterozoic but also a new calibration point for molecular clock estimates of early eukaryotic evolution, and in particular of the Opisthokontes. Collectively, these studies show that northwestern Canada is an exceptional window on early eukaryotes evolution. [less ▲]

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See detailPhototrophic green algae in Mid-Proterozoic oceans
Sforna, Marie-Catherine ULiege; Loron, Corentin ULiege; Demoulin, Catherine ULiege et al

Poster (2020, January)

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See detailDiversification of complex life on the early Earth: the Proterozoic of Artic Canada as a case study
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Rob et al

Poster (2020)

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See detailInterpreting the biological affinities of early Eukaryotes
Loron, Corentin ULiege; François, Camille; Rainbird, Rob et al

Conference (2020)

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See detailThe Proterozoic Arctic Canada as a case study for the evolution and diversity of early Eukaryotes.
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Rob et al

Poster (2020)

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See detailEvolution and diversity of early Eukaryotes: insights from the Proterozoic of Arctic Canada
Loron, Corentin ULiege; Halverson, Galen; Rainbird, Robert et al

Poster (2019, May)

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See detailAn early fungus from the Proterozoic of Arctic Canada
Loron, Corentin ULiege; Javaux, Emmanuelle ULiege

Conference (2019)

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See detailOrganic-walled microfossils from the late Mesoproterozoic to early Neoproterozoic lower Shaler Supergroup (Arctic Canada): Diversity and biostratigraphic significance
Loron, Corentin ULiege; Rainbird, Robert; Turner, Elizabeth et al

in Precambrian Research (2019), 321

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See detailEarly fungi from the Proterozoic era in Arctic Canada
Loron, Corentin ULiege; François, Camille; Rainbird, Robert et al

in Nature (2019)

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See detailAn early fungus in the Proterozoic of Arctic Canada
Loron, Corentin ULiege; François, Camille; Rainbird, Rob et al

Conference (2019)

Detailed reference viewed: 22 (2 ULiège)