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Saleh F, Clements T, Perrier V, Daley AC, Antcliffe JB. Variations in preservation of exceptional fossils within concretions. SWISS JOURNAL OF PALAEONTOLOGY 2023; 142:20. [PMID: 37719137 PMCID: PMC10501951 DOI: 10.1186/s13358-023-00284-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/13/2023] [Indexed: 09/19/2023]
Abstract
Concretions are an interesting mode of preservation that can occasionally yield fossils with soft tissues. To properly interpret these fossils, an understanding of their fossilization is required. Probabilistic models are useful tools to identify variations between different Konservat-Lagerstätten that are separated spatially and temporally. However, the application of probabilistic modeling has been limited to Early Paleozoic Konservat-Lagerstätten preserved in shales. In this paper, the patterns of preservation of three concretionary Konservat-Lagerstätten-the Carboniferous Mazon Creek (USA) and Montceau-les-Mines (France), and the Silurian Herefordshire Lagerstätte (UK)-are analyzed using a statistical approach. It is demonstrated that the degree of biotic involvement, i.e., the degree to which a carcass dictates its own preservation, is connected to internal organ conditional probabilities-the probabilities of finding an internal organ associated with another structure such as biomineralized, sclerotized, cuticularized, or cellular body walls. In concretions that are externally forced with little biological mediation (e.g., Herefordshire), all internal organ conditional probabilities are uniform. As biological mediation in concretion formation becomes more pronounced, heterogeneities in conditional probabilities are introduced (e.g., Montceau-les-Mines and Mazon Creek). The three concretionary sites were also compared with previously investigated Konservat-Lagerstätten preserving fossils in shales to demonstrate how the developed probability framework aids in understanding the broad-scale functioning of preservation in Konservat-Lagerstätten. Supplementary Information The online version contains supplementary material available at 10.1186/s13358-023-00284-4.
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Affiliation(s)
- Farid Saleh
- Institute of Earth Sciences (ISTE), University of Lausanne, Geopolis, CH-1015 Lausanne, Switzerland
| | - Thomas Clements
- GeoZentrum Nordbayern, Friedrich-Alexander Universität Erlangen-Nürnberg, Loewenichstrasse 28, 91054 Erlangen, Germany
| | - Vincent Perrier
- Université de Lyon, UCBL, ENSL, CNRS, UMR 5276 LGL-TPE, 69622 Villeurbanne, France
| | - Allison C Daley
- Institute of Earth Sciences (ISTE), University of Lausanne, Geopolis, CH-1015 Lausanne, Switzerland
| | - Jonathan B Antcliffe
- Institute of Earth Sciences (ISTE), University of Lausanne, Geopolis, CH-1015 Lausanne, Switzerland
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Miguel M, Kim SH, Lee SS, Cho YI. Composition and functional diversity of bacterial communities during swine carcass decomposition. Anim Biosci 2023; 36:1453-1464. [PMID: 37402447 PMCID: PMC10472150 DOI: 10.5713/ab.23.0140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/08/2023] [Accepted: 06/14/2023] [Indexed: 07/06/2023] Open
Abstract
OBJECTIVE This study investigated the changes in bacterial communities within decomposing swine microcosms, comparing soil with or without intact microbial communities, and under aerobic and anaerobic conditions. METHODS The experimental microcosms consisted of four conditions: UA, unsterilized soil-aerobic condition; SA, sterilized soil-aerobic condition; UAn, unsterilized soil-anaerobic condition; and San, sterilized soil-anaerobic condition. The microcosms were prepared by mixing 112.5 g of soil and 37.5 g of ground carcass, which were then placed in sterile containers. The carcass-soil mixture was sampled at day 0, 5, 10, 30, and 60 of decomposition, and the bacterial communities that formed during carcass decomposition were assessed using Illumina MiSeq sequencing of the 16S rRNA gene. RESULTS A total of 1,687 amplicon sequence variants representing 22 phyla and 805 genera were identified in the microcosms. The Chao1 and Shannon diversity indices varied in between microcosms at each period (p<0.05). Metagenomic analysis showed variation in the taxa composition across the burial microcosms during decomposition, with Firmicutes being the dominant phylum, followed by Proteobacteria. At the genus level, Bacillus and Clostridium were the main genera within Firmicutes. Functional prediction revealed that the most abundant Kyoto encyclopedia of genes and genomes metabolic functions were carbohydrate and amino acid metabolisms. CONCLUSION This study demonstrated a higher bacteria diversity in UA and UAn microcosms than in SA and SAn microcosms. In addition, the taxonomic composition of the microbial community also exhibited changes, highlighting the impact of soil sterilization and oxygen on carcass decomposition. Furthermore, this study provided insights into the microbial communities associated with decomposing swine carcasses in microcosm.
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Affiliation(s)
- Michelle Miguel
- Department of Animal Science and Technology, Sunchon National University, Suncheon, Jeonnam 57922,
Korea
| | - Seon-Ho Kim
- Department of Animal Science and Technology, Sunchon National University, Suncheon, Jeonnam 57922,
Korea
| | - Sang-Suk Lee
- Department of Animal Science and Technology, Sunchon National University, Suncheon, Jeonnam 57922,
Korea
| | - Yong-Il Cho
- Department of Animal Science and Technology, Sunchon National University, Suncheon, Jeonnam 57922,
Korea
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Gibson BM, Schiffbauer JD, Wallace AF, Darroch SAF. The role of iron in the formation of Ediacaran 'death masks'. GEOBIOLOGY 2023; 21:421-434. [PMID: 36843397 DOI: 10.1111/gbi.12551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/30/2023] [Accepted: 02/12/2023] [Indexed: 06/13/2023]
Abstract
The Ediacara biota are an enigmatic group of Neoproterozoic soft-bodied fossils that mark the first major radiation of complex eukaryotic and macroscopic life. These fossils are thought to have been preserved via pyritic "death masks" mediated by seafloor microbial mats, though little about the chemical constraints of this preservational pathway is known, in particular surrounding the role of bioavailable iron in death mask formation and preservational fidelity. In this study, we perform decay experiments on both diploblastic and triploblastic animals under a range of simulated sedimentary iron concentrations, in order to characterize the role of iron in the preservation of Ediacaran organisms. After 28 days of decay, we demonstrate the first convincing "death masks" produced under experimental laboratory conditions composed of iron sulfide and probable oxide veneers. Moreover, our results demonstrate that the abundance of iron in experiments is not the sole control on death mask formation, but also tissue histology and the availability of nucleation sites. This illustrates that Ediacaran preservation via microbial death masks need not be a "perfect storm" of paleoenvironmental porewater and sediment chemistry, but instead can occur under a range of conditions.
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Affiliation(s)
- Brandt M Gibson
- Department of Earth & Environmental Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - James D Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, Missouri, USA
- X-ray Microanalysis Core Facility, University of Missouri, Columbia, Missouri, USA
| | - Adam F Wallace
- Department of Geological Sciences, University of Delaware, Newark, Delaware, USA
| | - Simon A F Darroch
- Department of Earth & Environmental Sciences, Vanderbilt University, Nashville, Tennessee, USA
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Mähler B, Janssen K, Lönartz MI, Lagos M, Geisler T, Rust J, Bierbaum G. Time-dependent microbial shifts during crayfish decomposition in freshwater and sediment under different environmental conditions. Sci Rep 2023; 13:1539. [PMID: 36707669 PMCID: PMC9883499 DOI: 10.1038/s41598-023-28713-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Fossilization processes and especially the role of bacterial activity during the preservation of organic material has not yet been well understood. Here, we report the results of controlled taphonomic experiments with crayfish in freshwater and sediment. 16S rRNA amplicon analyzes showed that the development of the bacterial community composition over time was correlated with different stages of decay and preservation. Three dominating genera, Aeromonas, Clostridium and Acetobacteroides were identified as the main drivers in the decomposition of crayfish in freshwater. Using micro-computed tomography (µ-CT), scanning electron microscopy (SEM) and confocal Raman spectroscopy (CRS), calcite clusters were detected after 3-4 days inside crayfish carcasses during their decomposition in freshwater at 24 °C. The precipitation of calcite clusters during the decomposition process was increased in the presence of the bacterial genus Proteocatella. Consequently, Proteocatella might be one of the bacterial genera responsible for fossilization.
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Affiliation(s)
- Bastian Mähler
- Section Paleontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany.
| | - Kathrin Janssen
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität Bonn, 53127, Bonn, Germany.
| | - Mara Iris Lönartz
- Section Geochemistry, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115, Bonn, Germany.,Institute of Energy and Climate Research (IEK-6): Nuclear Waste Management, Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Markus Lagos
- Section Geochemistry, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115, Bonn, Germany
| | - Thorsten Geisler
- Section Geochemistry, Institute of Geosciences, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115, Bonn, Germany
| | - Jes Rust
- Section Paleontology, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität Bonn, 53127, Bonn, Germany
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Zhang G, Parry LA, Vinther J, Ma X. Exceptional soft tissue preservation reveals a cnidarian affinity for a Cambrian phosphatic tubicolous enigma. Proc Biol Sci 2022; 289:20221623. [PMID: 36321492 PMCID: PMC9627713 DOI: 10.1098/rspb.2022.1623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Exoskeletal dwelling tubes are widespread among extant animals and early fossil assemblages. Exceptional fossils from the Cambrian reveal independent origins of tube dwelling by several clades including cnidarians, lophophorates, annelids, scalidophorans, panarthropods and ambulacrarians. However, most fossil tubes lack preservation of soft parts, making it difficult to understand their affinities and evolutionary significance. Gangtoucunia aspera (Wulongqing Formation, Cambrian Stage 4) was an annulated, gradually expanding phosphatic tube, with occasional attachments of multiple, smaller juveniles and has previously been interpreted as the dwelling tube of a ‘worm’ (e.g. a scalidophoran), lophophorate or problematicum. Here, we report the first soft tissues from Gangtoucunia that reveal a smooth body with circumoral tentacles and a blind, spacious gut that is partitioned by septa. This is consistent with cnidarian polyps and phylogenetic analysis resolves Gangtoucunia as a total group medusozoan. The tube of Gangtoucunia is phenotypically similar to problematic annulated tubular fossils (e.g. Sphenothallus, Byronia, hyolithelminths), which have been compared to both cnidarians and annelids, and are among the oldest assemblages of skeletal fossils. The cnidarian characters of G. aspera suggest that these early tubular taxa are best interpreted as cnidarians rather than sessile bilaterians in the absence of contrary soft tissue evidence.
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Affiliation(s)
- Guangxu Zhang
- Yunnan Key Laboratory for Palaeobiology and MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, People's Republic of China
| | - Luke A. Parry
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Jakob Vinther
- Schools of Earth Sciences and Biological Sciences, University of Bristol, Bristol, UK
| | - Xiaoya Ma
- Yunnan Key Laboratory for Palaeobiology and MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, People's Republic of China
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
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Saleh F, Ma X, Guenser P, Mángano MG, Buatois LA, Antcliffe JB. Probability-based preservational variations within the early Cambrian Chengjiang biota (China). PeerJ 2022; 10:e13869. [PMID: 36032952 PMCID: PMC9415357 DOI: 10.7717/peerj.13869] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/19/2022] [Indexed: 01/18/2023] Open
Abstract
The Chengjiang biota (Yunnan Province, China) is a treasure trove of soft-bodied animal fossils from the earliest stages of the Cambrian explosion. The mechanisms contributing to its unique preservation, known as the Burgess Shale-type preservation, are well understood. However, little is known about the preservation differences between various animal groups within this biota. This study compares tissue-occurrence data of 11 major animal groups in the Chengjiang biota using a probabilistic methodology. The fossil-based data from this study is compared to previous decay experiments. This shows that all groups are not equally preserved with some higher taxa more likely to preserve soft tissues than others. These differences in fossil preservation between taxa can be explained by the interaction of biological and environmental characteristics. A bias also results from differential taxonomic recognition, as some taxa are easily recognized from even poorly preserved fragments while other specimens are difficult to assign to higher taxa even with exquisite preservation.
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Affiliation(s)
- Farid Saleh
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China,Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming, China
| | - Xiaoya Ma
- MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, Kunming, China,Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming, China,Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Pauline Guenser
- University Bordeaux, CNRS, Bordeaux INP, EPOC, UMR5805, Pessac, France
| | - M. Gabriela Mángano
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Luis A. Buatois
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Canada
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Janssen K, Mähler B, Rust J, Bierbaum G, McCoy VE. The complex role of microbial metabolic activity in fossilization. Biol Rev Camb Philos Soc 2021; 97:449-465. [PMID: 34649299 DOI: 10.1111/brv.12806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 12/22/2022]
Abstract
Bacteria play an important role in the fossilization of soft tissues; their metabolic activities drive the destruction of the tissues and also strongly influence mineralization. Some environmental conditions, such as anoxia, cold temperatures, and high salinity, are considered widely to promote fossilization by modulating bacterial activity. However, bacteria are extremely diverse, and have developed metabolic adaptations to a wide range of stressful conditions. Therefore, the influence of the environment on bacterial activity, and of their metabolic activity on fossilization, is complex. A number of examples illustrate that simple, general assumptions about the role of bacteria in soft tissue fossilization cannot explain all preservational pathways: (i) experimental results show that soft tissues of cnidaria decay less in oxic than anoxic conditions, and in the fossil record are found more commonly in fossil sites deposited under oxic conditions rather than anoxic environments; (ii) siderite concretions, which often entomb soft tissue fossils, precipitate due to a complex mixture of sulfate- and iron reduction by some bacterial species, running counter to original theories that iron reduction is the primary driver of siderite concretion growth; (iii) arthropod brains, now widely accepted to be preserved in many Cambrian fossil sites, are one of the first structures to decay in taphonomic experiments, indicating that their fossilization processes are complex and influenced by bacterial activity. In order to expand our understanding of the complex process of bacterially driven soft tissue fossilization, more research needs to be done, on fossils themselves and in taphonomic experiments, to determine how the complex variation in microbial metabolic activity influences decay and mineralization.
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Affiliation(s)
- Kathrin Janssen
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Bastian Mähler
- Paleontology Section, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Jes Rust
- Paleontology Section, Institute of Geosciences, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology, Medical Faculty, Rheinische Friedrich-Wilhelms Universität, 53127, Bonn, Germany
| | - Victoria E McCoy
- Department of Geosciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53211, U.S.A
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Saleh F, Daley AC, Lefebvre B, Pittet B, Perrillat JP. Biogenic Iron Preserves Structures during Fossilization: A Hypothesis: Iron from Decaying Tissues May Stabilize Their Morphology in the Fossil Record. Bioessays 2020; 42:e1900243. [PMID: 32338399 DOI: 10.1002/bies.201900243] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/27/2020] [Indexed: 11/12/2022]
Abstract
It is hypothesized that iron from biological tissues, liberated during decay, may have played a role in inhibiting loss of anatomical information during fossilization of extinct organisms. Most tissues in the animal kingdom contain iron in different forms. A widely distributed iron-bearing molecule is ferritin, a globular protein that contains iron crystallites in the form of ferrihydrite minerals. Iron concentrations in ferritin are high and ferrihydrites are extremely reactive. When ancient animals are decaying on the sea floor under anoxic environmental conditions, ferrihydrites may initialize the selective replication of some tissues in pyrite FeS2 . This model explains why some labile tissues are preserved, while other more resistant structures decay and are absent in many fossils. A major implication of this hypothesis is that structures described as brains in Cambrian arthropods are not fossilization artifacts, but are instead a source of information on anatomical evolution at the dawn of complex animal life.
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Affiliation(s)
- Farid Saleh
- Université de Lyon, Université Claude Bernard Lyon1, École Normale Supérieure de Lyon, CNRS, UMR5276, LGL-TPE, Villeurbanne, 69622, France
| | - Allison C Daley
- Institute of Earth Sciences, University of Lausanne, Géopolis, Lausanne, CH-1015, Switzerland
| | - Bertrand Lefebvre
- Université de Lyon, Université Claude Bernard Lyon1, École Normale Supérieure de Lyon, CNRS, UMR5276, LGL-TPE, Villeurbanne, 69622, France
| | - Bernard Pittet
- Université de Lyon, Université Claude Bernard Lyon1, École Normale Supérieure de Lyon, CNRS, UMR5276, LGL-TPE, Villeurbanne, 69622, France
| | - Jean Philippe Perrillat
- Université de Lyon, Université Claude Bernard Lyon1, École Normale Supérieure de Lyon, CNRS, UMR5276, LGL-TPE, Villeurbanne, 69622, France
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