Network analyses on photographic surveys reveal that invertebrate predators do not structure epibenthos in the deep (~2000m) rocky Powell Basin, Weddell Sea, Antarctica

Predator-prey interactions in marine ecosystems control population sizes, maintain species richness, and provide intermediate disturbance. Such ecosystem structuring interactions may be rare in Antarctic epibenthic communities, which are unique among marine ecosystems worldwide for their dominance of soft bodied fauna (sponges, soft and hard corals, and echinoderms) and a simultaneous paucity of shell crushing predators (sharks, rays and durophagous decapods). In the shallow benthos, instead of durophagy, important Antarctic predators such as starfish, pycnogonids (sea spiders), nemertean worms, and nudibranchs employ grazing, scavenging, or sucking strategies. Far less is known about deep sea (>1000 m) Antarctic benthic communities due to the challenging nature of polar data collection, so that photographic surveys provide one of the only means of making in situ observations of these deep sea communities. We used seabed photographs of the deep (~2000m) slope of the Powell Basin, northwest Weddell Sea, taken by the Ocean Floor Observation and Bathymetry System on board the RV Polarstern (PS118, April 2019) to investigate the epibenthic community composition, and Bayesian Network Inference (BNI) to determine the ecological network, namely the ecological associations, including potential invertebrate predator-prey relationships between taxa. Photographs show that the rocky substrates of the basin slope support between 10-22 morphotaxa per photo, and highly abundant communities (density between 106 to 553 individuals/m2). BNI results reveal a network of associations between the sessile and mobile suspension and filter feeding organisms and their physical environment. However, associations between invertebrate predators like starfish, and other organisms, were not detected in the network. This lack of inclusion within the network suggests that, despite the presence of these normally important mobile predators, invertebrate predator-prey interactions on the rocky Powell Basin slope do not have the same ecosystem-regulating impact that they do on shallow Antarctic epibenthic communities

Supplementary Material from ‘Conga lines’ of Ediacaran fronds: insights into the reproductive biology of early metazoans

SI_Congas_2902_REVISED.doc

Supplementary Material from ‘Conga lines’ of Ediacaran fronds: insights into the reproductive biology of early metazoans

SI_Congas_2902_REVISED_blank.doc

Morphology shapes community dynamics in early animal ecosystems

Acknowledgements: Funding was provided by an School of Biological Sciences Balfour Studentship (PFAG/076) to N.P.S.; a Natural Environment Research Council C-CLEAR DTP studentship (LBAG/265.03.G10) to K.M.D.; Leverhulme Trust Funding (ECF-2018-542) and from the Isaac Newton Trust (INT18.08(h)) to C.G.K.; a Natural Environment Research Council Standard Grant (NE/P002412/1) and an Independent Research Fellowship (NE/S014756/1) to E.G.M. The Parks and Natural Areas Division, Department of Environment and Conservation, Government of Newfoundland and Labrador, provided permits to conduct research within the MPER in 2010, 2016–2018 and 2021–2023. Readers are advised that access to MPER is by scientific research permit only. Fossil surfaces in the Bonavista Peninsula and Bay Roberts area are protected under reg. 67/11, of the Historic Resources Act 2011 and their access is only allowed under permit from the Government of Newfoundland and Labrador. Fieldwork in the Discovery Geopark and the Bay Roberts area was conducted under permit from the Government of Newfoundland and Labrador. Bed B forms part of a designated Site of Special Scientific Interest, protected in law and administered by Natural England. Access to Bed B casts was facilitated by BGS and P. Wilby. We thank S. Pates and F. Dunn for discussions, B. Jewer for image processing and J. Durden for support with the methods. We thank E. Samson for everything she does to support us and our work.Funder: Independent Research Fellowship NE/S014756/1Funder: School of Biological Science Balfour StudentshipFunder: RCUK | Natural Environment Research Council (NERC); doi: https://doi.org/10.13039/501100000270Funder: ECF-2018-542, INT18.08(h)The driving forces behind the evolution of early metazoans are not well understood, but key insights into their ecology and evolution can be gained through ecological analyses of the in situ, sessile communities of the Avalon assemblage in the Ediacaran (~565 million years ago). Community structure in the Avalon is thought to be underpinned by epifaunal tiering and ecological succession, which we investigate in this study in 18 Avalon communities. Here we found that Avalon communities form four distinctive Community Types irrespective of succession processes, which are instead based on the dominance of morphologically distinct taxa, and that tiering is prevalent in three of these Community Types. Our results are consistent with emergent neutrality, whereby ecologically specialized morphologies evolve as a consequence of neutral (stochastic or reproductive) processes within niches, leading to generalization within the frond-dominated Community Type. Our results provide an ecological signature of the first origination and subsequent loss of disparate morphologies, probably as a consequence of community restructuring in response to ecological innovation. This restructuring led to the survival of non-tiered frondose generalists over tiered specialists, even into the youngest Ediacaran assemblages. Such frondose body plans also survive beyond the Ediacaran–Cambrian transition, perhaps due to the greater resilience afforded to them by their alternative ecological strategies

Morphology shapes community dynamics in early animal ecosystems

Acknowledgements: Funding was provided by an School of Biological Sciences Balfour Studentship (PFAG/076) to N.P.S.; a Natural Environment Research Council C-CLEAR DTP studentship (LBAG/265.03.G10) to K.M.D.; Leverhulme Trust Funding (ECF-2018-542) and from the Isaac Newton Trust (INT18.08(h)) to C.G.K.; a Natural Environment Research Council Standard Grant (NE/P002412/1) and an Independent Research Fellowship (NE/S014756/1) to E.G.M. The Parks and Natural Areas Division, Department of Environment and Conservation, Government of Newfoundland and Labrador, provided permits to conduct research within the MPER in 2010, 2016–2018 and 2021–2023. Readers are advised that access to MPER is by scientific research permit only. Fossil surfaces in the Bonavista Peninsula and Bay Roberts area are protected under reg. 67/11, of the Historic Resources Act 2011 and their access is only allowed under permit from the Government of Newfoundland and Labrador. Fieldwork in the Discovery Geopark and the Bay Roberts area was conducted under permit from the Government of Newfoundland and Labrador. Bed B forms part of a designated Site of Special Scientific Interest, protected in law and administered by Natural England. Access to Bed B casts was facilitated by BGS and P. Wilby. We thank S. Pates and F. Dunn for discussions, B. Jewer for image processing and J. Durden for support with the methods. We thank E. Samson for everything she does to support us and our work.Funder: Independent Research Fellowship NE/S014756/1Funder: School of Biological Science Balfour StudentshipFunder: RCUK | Natural Environment Research Council (NERC); doi: https://doi.org/10.13039/501100000270Funder: ECF-2018-542, INT18.08(h)The driving forces behind the evolution of early metazoans are not well understood, but key insights into their ecology and evolution can be gained through ecological analyses of the in situ, sessile communities of the Avalon assemblage in the Ediacaran (~565 million years ago). Community structure in the Avalon is thought to be underpinned by epifaunal tiering and ecological succession, which we investigate in this study in 18 Avalon communities. Here we found that Avalon communities form four distinctive Community Types irrespective of succession processes, which are instead based on the dominance of morphologically distinct taxa, and that tiering is prevalent in three of these Community Types. Our results are consistent with emergent neutrality, whereby ecologically specialized morphologies evolve as a consequence of neutral (stochastic or reproductive) processes within niches, leading to generalization within the frond-dominated Community Type. Our results provide an ecological signature of the first origination and subsequent loss of disparate morphologies, probably as a consequence of community restructuring in response to ecological innovation. This restructuring led to the survival of non-tiered frondose generalists over tiered specialists, even into the youngest Ediacaran assemblages. Such frondose body plans also survive beyond the Ediacaran–Cambrian transition, perhaps due to the greater resilience afforded to them by their alternative ecological strategies

Network analyses on photographic surveys reveal that invertebrate predators do not structure epibenthos in the deep (~2000m) rocky Powell Basin, Weddell Sea, Antarctica

Peer reviewed: TrueAcknowledgements: We thank all members of crew and participants of the RV Polarstern Expedition PS118, Laura Hehemann, Simon Dreutter, Boris Dorschel, and Axel Nordhausen for operating OFOBS and making photos available. We also thank Michelle Taylor, Christopher Mah, Estefania Rodriguez and Louise Allcock for helping us ID some specimens.Predator-prey interactions in marine ecosystems control population sizes, maintain species richness, and provide intermediate disturbance. Such ecosystem structuring interactions may be rare in Antarctic epibenthic communities, which are unique among marine ecosystems worldwide for their dominance of soft bodied fauna (sponges, soft and hard corals, and echinoderms) and a simultaneous paucity of shell crushing predators (sharks, rays and durophagous decapods). In the shallow benthos, instead of durophagy, important Antarctic predators such as starfish, pycnogonids (sea spiders), nemertean worms, and nudibranchs employ grazing, scavenging, or sucking strategies. Far less is known about deep sea (>1000 m) Antarctic benthic communities due to the challenging nature of polar data collection, so that photographic surveys provide one of the only means of making in situ observations of these deep sea communities. We used seabed photographs of the deep (~2000m) slope of the Powell Basin, northwest Weddell Sea, taken by the Ocean Floor Observation and Bathymetry System on board the RV Polarstern (PS118, April 2019) to investigate the epibenthic community composition, and Bayesian Network Inference (BNI) to determine the ecological network, namely the ecological associations, including potential invertebrate predator-prey relationships between taxa. Photographs show that the rocky substrates of the basin slope support between 10-22 morphotaxa per photo, and highly abundant communities (density between 106 to 553 individuals/m2). BNI results reveal a network of associations between the sessile and mobile suspension and filter feeding organisms and their physical environment. However, associations between invertebrate predators like starfish, and other organisms, were not detected in the network. This lack of inclusion within the network suggests that, despite the presence of these normally important mobile predators, invertebrate predator-prey interactions on the rocky Powell Basin slope do not have the same ecosystem-regulating impact that they do on shallow Antarctic epibenthic communities

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