Fossilisation processes and our reading of animal antiquity

Estimates for animal antiquity exhibit a significant disconnect between those from molecular clocks, which indicate crown animals evolved ∼800 million years ago (Ma), and those from the fossil record, which extends only ∼574 Ma. Taphonomy is often held culpable: early animals were too small/soft/fragile to fossilise, or the circumstances that preserve them were uncommon in the early Neoproterozoic. We assess this idea by comparing Neoproterozoic fossilisation processes with those of the Cambrian and its abundant animal fossils. Cambrian Burgess Shale-type (BST) preservation captures animals in mudstones showing a narrow range of mineralogies; yet, fossiliferous Neoproterozoic mudstones rarely share the same mineralogy. Animal fossils are absent where BST preservation occurs in deposits ≥789 Ma, suggesting a soft maximum constraint on animal antiquity

Sustained increases in atmospheric oxygen and marine productivity in the Neoproterozoic and Palaeozoic eras

A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system

Fossilisation processes and our reading of animal antiquity.

Estimates for animal antiquity exhibit a significant disconnect between those from molecular clocks, which indicate crown animals evolved ∼800 million years ago (Ma), and those from the fossil record, which extends only ∼574 Ma. Taphonomy is often held culpable: early animals were too small/soft/fragile to fossilise, or the circumstances that preserve them were uncommon in the early Neoproterozoic. We assess this idea by comparing Neoproterozoic fossilisation processes with those of the Cambrian and its abundant animal fossils. Cambrian Burgess Shale-type (BST) preservation captures animals in mudstones showing a narrow range of mineralogies; yet, fossiliferous Neoproterozoic mudstones rarely share the same mineralogy. Animal fossils are absent where BST preservation occurs in deposits ≥789 Ma, suggesting a soft maximum constraint on animal antiquity.Royal Societ

Palaeontology from Australasia and beyond: Abstracts from Palaeo Down Under 3 Perth, Western Australia, July 2023

Palaeo Down Under 3 (PDU3), the now quadrennial conference of the Australasian Palaeontologists (AAP) association, was held in Perth, Western Australia, from the 10th-14th of July 2023. PDU3 showcased innovative research, outreach and education initiatives being conducted across Australasia and beyond by both local and international scientists. A total of 78 talks, 17 posters and 6 plenaries were presented across the five days, and covered a wide range of topics, geological timeframes, and fossil groups. AAP is proud to publish this compilation of PDU3 abstracts to illustrate the current and ongoing strength of Australasian palaeontology. Sarah K. Martin [ [email protected] ], Geological Survey of Western Australia, Department of Energy, Mines, Industry Regulation and Safety, 100 Plain St, East Perth, Western Australia 6004, Australia; Michael Archer [ [email protected] ], School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia; Heidi J. Allen [ [email protected] ], Geological Survey of Western Australia, Department of Energy, Mines, Industry Regulation and Safety, 100 Plain St, East Perth, Western Australia 6004, Australia; Daniel D. Badea [ [email protected] ], Faculty of Geography and Geology, "Alexandru Ioan Cuza" University, Bulevard "Carol I", Nr.11, 707006, Iași, Romania; Eleanor Beidatsch [ [email protected] ], Palaeoscience Research Centre, University of New England, Armidale, New South Wales 2351, Australia; Marissa J. Betts [ [email protected] ], Palaeoscience Research Centre/LLUNE, University of New England, Armidale, New South Wales 2351, Australia; Maria Blake [ [email protected] ], School of Earth, Atmosphere and Environment, Monash University, 9 Rainforest Walk, Clayton, Victoria 3800, Australia; Phillip C. Boan [ [email protected] ], University of California, Riverside, Geology 1242, 900 University Ave, Riverside, CA 92521, U.S.A.; Tory Botha [ [email protected] ], School of Biological Sciences, Molecular Life Sciences Building, North Terrace Campus, The University of Adelaide, Adelaide, South Australia 5005, Australia; Glenn A. Brock [ [email protected] ], School of Natural Sciences, Macquarie University, New South Wales 2109, Australia; Luke Brosnan [ [email protected] ], WA Organic and Isotope Geochemistry Centre, The Institute for Geoscience Research, School of Earth and Planetary Sciences, Building 500, Curtin University, Kent St, Bentley, Western Australia 6102, Australia; Jack Castle-Jones [ [email protected] ], School of Natural Sciences, Macquarie University, New South Wales 2109, Australia; Jonathan Cramb [ [email protected] ], Queensland Museum, PO Box 3300, South Brisbane BC, Queensland 4101, Australia; Vanesa L. De Pietri [ [email protected] ], School of Earth and Environment, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand; Sherri Donaldson [ [email protected] ], School of Geosciences, University of Edinburgh, Grant Institute, The King's Buildings, James Hutton Road, Edinburgh, EH9 3FE, Scotland, U.K.; Elizabeth M. Dowding [ [email protected] ], Friedrich-Alexander-Universität Erlangen-Nürnberg, Loewenichstraße 28 91054 Erlangen, Germany; Ruairidh Duncan [ [email protected] ], Evans EvoMorph Lab, Room 226, 18 Innovation Walk, School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia; Amy L. Elson [ [email protected] ], WA Organic and Isotope Geochemistry Centre, The Institute for Geoscience Research, School of Earth and Planetary Sciences, Building 500, Curtin University, Kent St, Bentley, Western Australia 6102, Australia; Roy M. Farman [ [email protected] ], School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia; Mahala A. Fergusen [ [email protected] ], School of Biological Sciences, Benham Building, North Terrace Campus, The University of Adelaide, Adelaide, South Australia 5005, Australia; Alyssa Fjeld [ [email protected] ], School of Biological Sciences, 18 Innovation Walk, Monash University, Clayton, Victoria 3800, and School of Natural Sciences, Macquarie University, New South Wales 2109, Australia; David Flannery [ [email protected] ], School of Earth and Atmospheric Sciences, Queensland University of Technology, 2 George St, Brisbane, Queensland 4000, Australia; Timothy G. Frauenfelder [ [email protected] ], University of New England, Armidale, New South Wales 2351, Australia; John D. Gorter [ [email protected] ], PO Box 711, Claremont, Western Australia 6910, Australia; Michelle Gray [ [email protected] ], School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216, Australia; Nigel Gray [ [email protected] ], GPO Box 2902, Brisbane, Queensland 4001, Australia; Peter Haines [ [email protected] ], Geological Survey of Western Australia, Department of Energy, Mines, Industry Regulation and Safety, 100 Plain St, East Perth, Western Australia 6004, Australia; Lachlan J. Hart [ [email protected] ], Australian Museum Research Institute, 1 William Street, Sydney, New South Wales 2010, Australia; Brooke E. Holland [ [email protected] ], School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia; James D. Holmes [ [email protected] ], Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala 752 36, Sweden; Lars Holmer [ [email protected] ], Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, Uppsala 752 36, Sweden; Ashleigh V.S. Hood [ [email protected] ], School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, Victoria 3010, Australia; Alexey P. Ippolitov [ [email protected]] , School of Geography, Environment and Earth Sciences, Victoria University of Wellington | Te Herenga Waka, 21 Kelburn Parade, Wellington 6012, New Zealand; Christine M. Janis [ [email protected] ], Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, BS8 1RJ, U.K.; Benjamin P. Kear [ [email protected] ], The Museum of Evolution, Uppsala University, Norbyvägen 16, SE-752 36 Uppsala, Sweden; Sophie Kelly [ [email protected] ], School of Earth and Environment, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand; Justin L. Kitchener [ [email protected] ], School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia; John R. Laurie [ [email protected] ], Geoscience Australia, Symonston, Australian Capital Territory 2601, and School of Natural Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia; Lucy G. Leahey [ [email protected] ], The University of Queensland, Brisbane, Queensland 4072, Australia; John A. Long [ [email protected] ], College of Science and Engineering, Flinders University, PO Box 2100, Adelaide, South Australia 5001, Australia; Daniel Mantle [ [email protected] ], MGPalaeo, Unit 1, 5 Arvida Street, Malaga, Western Australia 6090, Australia; David McB. Martin [ [email protected] ], Geological Survey of Western Australia, Department of Energy, Mines, Industry Regulation and Safety, 100 Plain St, East Perth, Western Australia 6004, Australia; Chris Mays [ [email protected] ], School of Biological, Earth and Environmental Sciences, Environmental Research Institute, University College Cork, Distillery Fields, Cork T23 N73K, Ireland; Matthew R. McCurry [ [email protected] ], Australian Museum, 1 William St, Sydney, New South Wales 2010, Australia; Peter McGoldrick [ [email protected] ], CODES, University of Tasmania, Locked Bag 66, Hobart, Tasmania 7001, Australia; Corinne L. Mensforth [ [email protected] ], Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia; Rhys D. Meyerkort [ [email protected] ], University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia; Christina Nielsen-Smith [ [email protected] ], School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia; Ryan Nel [ [email protected] ], Geology Department, Rhodes University, Grahamstown, South Africa; Jake Newman-Martin [ [email protected] ], Curtin University, Kent St, Bentley, Western Australia 6102, Australia; Yeongju Oh [ [email protected] ], Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, 21990 Incheon, Republic of Korea, and Polar Science, University of Science and Technology, Daejeon, 34113, Republic of Korea; John R. Paterson [ [email protected] ], Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia; Jacob Pears [ [email protected] ], School of Molecular and Life Sciences, Curtin University, Kent St, Bentley, Western Australia 6102, Australia; Stephen F. Poropat [ [email protected] ], Western Australian Organic and Isotope Geochemistry Centre, School of Earth and Planetary Science, Curtin University, Kent St, Bentley, Western Australia 6102, and Australian Age of Dinosaurs Museum of Natural History, Winton, Queensland 4735, Australia; Catherine M. Reid [ [email protected] ], School of Earth and Environment, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand; R. Pamela Reid [ [email protected] ], Department of Marine Geosciences, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149, U.S.A., and Bahamas Marine EcoCentre, Miami, FL 3315

Sustained increases in atmospheric oxygen and marine productivity in the Neoproterozoic and Palaeozoic eras

International audienceA geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system

The Sedimentary Geochemistry and Paleoenvironments Project.

Authors thank the donors of The American Chemical Society Petroleum Research Fund for partial support of SGP website development (61017-ND2). EAS is funded by National Science Foundation grant (NSF) EAR-1922966. BGS authors (JE, PW) publish with permission of the Executive Director of the British Geological Survey, UKRI.Publisher PDFPeer reviewe