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Zeng W, Jiang H, Chen Y, Ogg J, Zhang M, Dong H. Upper Norian conodonts from the Baoshan block, western Yunnan, southwestern China, and implications for conodont turnover. PeerJ 2023; 11:e14517. [PMID: 36684668 PMCID: PMC9854380 DOI: 10.7717/peerj.14517] [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: 12/01/2021] [Accepted: 11/15/2022] [Indexed: 01/18/2023] Open
Abstract
The Sevatian of the late Norian is one of the key intervals in biotic turnover and in changes of paleoclimate and paleoenvironments. Conodont faunas recovered from two sections of upper Norian strata of the Dashuitang and Nanshuba formations near Baoshan City in western Yunnan province provide new insights into the diversity and biostratigraphy of the Sevatian conodonts within China as well as globally. A lower Mockina (M.) bidentata Zone and an upper Parvigondolella (P.) andrusovi Zone are identified in this area according to the first occurrences of M. bidentata and of P. andrusovi. Rich conodont fauna of M. zapfei is detailed and presents various intraspecific forms. A total of 19 forms of P1 elements are presented, which, when combined with the reported conodonts in the M. bidentata Zone, suggest that there was a peak in conodont diversity within the M. bidentata Zone. A biotic crisis in the uppermost M. bidentata Zone is recognized from the contrast between the diverse conodont fauna in the M. bidentata Zone and the rare conodonts in the P. andrusovi Zone. The conodont turnover during the middle Sevatian highlights the fact that the prolonged phases of the end-Triassic mass extinction probably began in the transition interval from M. bidentata Zone to P. andrusovi Zone.
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Affiliation(s)
- Weiping Zeng
- School of Geography and Tourism, Huanggang Normal University, Huanggang, Hubei, P. R. China,State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Haishui Jiang
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Yan Chen
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - James Ogg
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China,Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, United States
| | - Muhui Zhang
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
| | - Hanxinshuo Dong
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, Hubei, China
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Lin S, Hou L, Luo X, Wu Y. A millimeter-scale insight into formation mechanism of lacustrine black shale in tephra deposition background. Sci Rep 2022; 12:11511. [PMID: 35798815 PMCID: PMC9262940 DOI: 10.1038/s41598-022-15715-4] [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] [Received: 03/21/2022] [Accepted: 06/28/2022] [Indexed: 11/15/2022] Open
Abstract
To reveal the role of tephra in the deposition of black shale during periods of volcanic activity, we performed lithostratigraphic and geochemical analyses on 14 horizontally sliced samples drilled from a 2-cm-thick black shale interval in the lower Ch7 Member of the Upper Triassic Yanchang Formation, southern Ordos Basin. Results indicate that fewer plankton is preserved during tephra deposition than during periods of volcanic quiescence. With the decrease of volcanic activities and tephra deposition, the abundance of redox-sensitive trace elements (RSTEs) and biolimiting elements increases, while terrigenous elements gradually decrease, resulting in the improvement of organic matter (OM) preservation. Paleoenvironmental proxies suggest that the climate during the Late Triassic was generally warm and humid. However, subsequent intense volcanic eruptions may have caused climatic cooling that affected the water column, resulting in enhanced salinity, primary production, water stratification, and bottom water anoxia, leading to enhanced organic carbon production and preservation. Primary productivity and redox conditions controlled the accumulation of organic carbon. Although physical and chemical reactions relating to the deposition of tephra into water are short-lived, climate change induced by volcanic eruptions is the critical cause of black shale formation.
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Affiliation(s)
- Senhu Lin
- Department of Oil and Gas Geology, Research Institute of Petroleum Exploration and Development, PetroChina, Xueyuan Road 20, Beijing, 100083, China.
| | - Lianhua Hou
- Central Laboratory of Geological Science, Research Institute of Petroleum Exploration and Development, PetroChina, Xueyuan Road 20, Beijing, 100083, China.
| | - Xia Luo
- Department of Oil and Gas Geology, Research Institute of Petroleum Exploration and Development, PetroChina, Xueyuan Road 20, Beijing, 100083, China.
| | - Yiwen Wu
- School of Energy Resource, China University of Geosciences, Xueyuan Road 29, Beijing, 100191, China
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3
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Dal Corso J, Bernardi M, Sun Y, Song H, Seyfullah LJ, Preto N, Gianolla P, Ruffell A, Kustatscher E, Roghi G, Merico A, Hohn S, Schmidt AR, Marzoli A, Newton RJ, Wignall PB, Benton MJ. Extinction and dawn of the modern world in the Carnian (Late Triassic). SCIENCE ADVANCES 2020; 6:6/38/eaba0099. [PMID: 32938682 PMCID: PMC7494334 DOI: 10.1126/sciadv.aba0099] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The Carnian Pluvial Episode (Late Triassic) was a time of global environmental changes and possibly substantial coeval volcanism. The extent of the biological turnover in marine and terrestrial ecosystems is not well understood. Here, we present a meta-analysis of fossil data that suggests a substantial reduction in generic and species richness and the disappearance of 33% of marine genera. This crisis triggered major radiations. In the sea, the rise of the first scleractinian reefs and rock-forming calcareous nannofossils points to substantial changes in ocean chemistry. On land, there were major diversifications and originations of conifers, insects, dinosaurs, crocodiles, lizards, turtles, and mammals. Although there is uncertainty on the precise age of some of the recorded biological changes, these observations indicate that the Carnian Pluvial Episode was linked to a major extinction event and might have been the trigger of the spectacular radiation of many key groups that dominate modern ecosystems.
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Affiliation(s)
- Jacopo Dal Corso
- School of Earth and Environments, University of Leeds, Leeds, LS2 9JT, UK.
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences Wuhan, Wuhan, China
| | - Massimo Bernardi
- MUSE-Science Museum, 38122 Trento, Italy
- School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
| | - Yadong Sun
- GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences Wuhan, Wuhan, China
| | - Leyla J Seyfullah
- Department of Palaeontology, University of Vienna, 1090 Wien, Austria
| | - Nereo Preto
- Department of Geosciences, University of Padova, 35131 Padova, Italy
| | - Piero Gianolla
- Department of Physics and Earth Sciences, University of Ferrara, 44100 Ferrara, Italy
| | - Alastair Ruffell
- School of Natural and Built Environment, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland, UK
| | - Evelyn Kustatscher
- Museum of Nature South Tyrol, 39100 Bozen/Bolzano, Italy
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany
- SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, 80333 München, Germany
| | - Guido Roghi
- Institute of Geosciences and Earth Resources (IGG-CNR), 35131 Padova, Italy
| | - Agostino Merico
- Leibniz Centre for Tropical Marine Research (ZMT), 28359 Bremen, Germany
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
| | - Sönke Hohn
- Leibniz Centre for Tropical Marine Research (ZMT), 28359 Bremen, Germany
| | | | - Andrea Marzoli
- Department of Geosciences, University of Padova, 35131 Padova, Italy
| | - Robert J Newton
- School of Earth and Environments, University of Leeds, Leeds, LS2 9JT, UK
| | - Paul B Wignall
- School of Earth and Environments, University of Leeds, Leeds, LS2 9JT, UK
| | - Michael J Benton
- School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK.
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Song H, Wignall PB, Dunhill AM. Decoupled taxonomic and ecological recoveries from the Permo-Triassic extinction. SCIENCE ADVANCES 2018; 4:eaat5091. [PMID: 30324133 PMCID: PMC6179380 DOI: 10.1126/sciadv.aat5091] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 09/05/2018] [Indexed: 05/04/2023]
Abstract
The Permian-Triassic mass extinction was the worst crisis faced by life; it killed >90% of marine species in less than 0.1 million years (Ma). However, knowledge of its macroecological impact over prolonged time scales is limited. We show that marine ecosystems dominated by non-motile animals shifted to ones dominated by nektonic groups after the extinction. In Triassic oceans, animals at high trophic levels recovered faster than those at lower levels. The top-down rebuilding of marine ecosystems was still underway in the latest Triassic, ~50 Ma after the extinction, and contrasts with the ~5-Ma recovery required for taxonomic diversity. The decoupling between taxonomic and ecological recoveries suggests that a process of vacant niche filling before reaching the maximum environmental carrying capacity is independent of ecosystem structure building.
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Affiliation(s)
- Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Science, China University of Geosciences, Wuhan 430074, China
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
- Corresponding author.
| | - Paul B. Wignall
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
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5
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Seyfullah LJ, Beimforde C, Dal Corso J, Perrichot V, Rikkinen J, Schmidt AR. Production and preservation of resins - past and present. Biol Rev Camb Philos Soc 2018; 93:1684-1714. [DOI: 10.1111/brv.12414] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Leyla J. Seyfullah
- Department of Geobiology; University of Göttingen; 37077 Göttingen Germany
| | | | - Jacopo Dal Corso
- Hanse-Wissenschaftskolleg, Institute for Advanced Study; 27753 Delmenhorst Germany
| | - Vincent Perrichot
- Univ Rennes, CNRS, Géosciences Rennes - UMR 6118; 35000 Rennes France
| | - Jouko Rikkinen
- Finnish Museum of Natural History, University of Helsinki; 00014 Helsinki Finland
- Faculty of Biological and Environmental Sciences; University of Helsinki; 00014 Helsinki Finland
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6
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Walther V, Hiley CT, Shibata D, Swanton C, Turner PE, Maley CC. Can oncology recapitulate paleontology? Lessons from species extinctions. Nat Rev Clin Oncol 2015; 12:273-85. [PMID: 25687908 PMCID: PMC4569005 DOI: 10.1038/nrclinonc.2015.12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Although we can treat cancers with cytotoxic chemotherapies, target them with molecules that inhibit oncogenic drivers, and induce substantial cell death with radiation, local and metastatic tumours recur, resulting in extensive morbidity and mortality. Indeed, driving a tumour to extinction is difficult. Geographically dispersed species of organisms are perhaps equally resistant to extinction, but >99.9% of species that have ever existed on this planet have become extinct. By contrast, we are nowhere near that level of success in cancer therapy. The phenomena are broadly analogous--in both cases, a genetically diverse population mutates and evolves through natural selection. The goal of cancer therapy is to cause cancer cell population extinction, or at least to limit any further increase in population size, to prevent the tumour burden from overwhelming the patient. However, despite available treatments, complete responses are rare, and partial responses are limited in duration. Many patients eventually relapse with tumours that evolve from cells that survive therapy. Similarly, species are remarkably resilient to environmental change. Paleontology can show us the conditions that lead to extinction and the characteristics of species that make them resistant to extinction. These lessons could be translated to improve cancer therapy and prognosis.
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Affiliation(s)
- Viola Walther
- Evolution and Cancer Laboratory, Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Crispin T Hiley
- Translational Cancer Therapeutics Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Darryl Shibata
- Department of Pathology, USC Keck School of Medicine, Hoffman Medical Research Center 211, 2011 Zonal Avenue, Los Angeles, CA 90089-9092, USA
| | - Charles Swanton
- Translational Cancer Therapeutics Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Paul E Turner
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Carlo C Maley
- Center for Evolution and Cancer, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143, USA
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7
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Deep-sea record of impact apparently unrelated to mass extinction in the Late Triassic. Proc Natl Acad Sci U S A 2012; 109:19134-9. [PMID: 23129649 DOI: 10.1073/pnas.1209486109] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 34-million-year (My) interval of the Late Triassic is marked by the formation of several large impact structures on Earth. Late Triassic impact events have been considered a factor in biotic extinction events in the Late Triassic (e.g., end-Triassic extinction event), but this scenario remains controversial because of a lack of stratigraphic records of ejecta deposits. Here, we report evidence for an impact event (platinum group elements anomaly with nickel-rich magnetite and microspherules) from the middle Norian (Upper Triassic) deep-sea sediment in Japan. This includes anomalously high abundances of iridium, up to 41.5 parts per billion (ppb), in the ejecta deposit, which suggests that the iridium-enriched ejecta layers of the Late Triassic may be found on a global scale. The ejecta deposit is constrained by microfossils that suggest correlation with the 215.5-Mya, 100-km-wide Manicouagan impact crater in Canada. Our analysis of radiolarians shows no evidence of a mass extinction event across the impact event horizon, and no contemporaneous faunal turnover is seen in other marine planktons. However, such an event has been reported among marine faunas and terrestrial tetrapods and floras in North America. We, therefore, suggest that the Manicouagan impact triggered the extinction of terrestrial and marine organisms near the impact site but not within the pelagic marine realm.
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8
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Abstract
Local extinctions of populations, species or groups of species in a particular area are commonly observed by biologists. There are also historical records of the total extinction of single species such as the Dodo, the Great Auk and the Tasmanian Wolf. Mass extinctions are on a much larger scale, and their study is based on the fossil record. The aims of this review are to explore the nature of mass extinctions and their evolutionary significance. The key questions are: what is mass extinction, what are the causes of mass extinctions, do mass extinctions follow a regular pattern, and how do mass extinctions affect our understanding of evolutionary processes?
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Affiliation(s)
- M J Benton
- Michael Benton is at the Department of Geology, The Queen's University of Belfast, Belfast BT7 1NN, UK
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9
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Sues HD, Olsen PE. Triassic vertebrates of gondwanan aspect from the richmond basin of virginia. Science 2010; 249:1020-3. [PMID: 17789610 DOI: 10.1126/science.249.4972.1020] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A new locality of early Late Triassic age in the Richmond basin of east-central Virginia has yielded abundant remains of a diversified assemblage of small to medium-sized tetrapods that closely resembles Southern Hemisphere (Gondwanan) assemblages in the predominance of certain synapsids. Associated palynomorphs indicate an early middle Carnian age for the fossiliferous strata. The discovery suggests that previously recognized differences between tetrapod assemblages of early Late Triassic age from Gondwana and Laurasia at least in part reflect differences in stratigraphic age, rather than geographic separation.
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10
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Langer MC, Ezcurra MD, Bittencourt JS, Novas FE. The origin and early evolution of dinosaurs. Biol Rev Camb Philos Soc 2010; 85:55-110. [DOI: 10.1111/j.1469-185x.2009.00094.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Ruffell A, McKinley JM, Worden RH. Comparison of clay mineral stratigraphy to other proxy palaeoclimate indicators in the Mesozoic of NW Europe. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2002; 360:675-693. [PMID: 12804299 DOI: 10.1098/rsta.2001.0961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper reviews the opportunities and pitfalls associated with using clay mineralogical analysis in palaeoclimatic reconstructions. Following this, conjunctive methods of improving the reliability of clay mineralogical analysis are reviewed. The Mesozoic succession of NW Europe is employed as a case study. This demonstrates the relationship between clay mineralogy and palaeoclimate. Proxy analyses may be integrated with clay mineralogical analysis to provide an assessment of aridity-humidity contrasts in the hinterland climate. As an example, the abundance of kaolinite through the Mesozoic shows that, while interpretations may be difficult, the Mesozoic climate of NW Europe was subject to great changes in rates of continental precipitation. We may compare sedimentological (facies, mineralogy, geochemistry) indicators of palaeoprecipitation with palaeotemperature estimates. The integration of clay mineralogical analyses with other sedimentological proxy indicators of palaeoclimate allows differentiation of palaeoclimatic effects from those of sea-level and tectonic change. We may also observe how widespread palaeoclimate changes were; whether they were diachronous or synchronous; how climate, sea level and tectonics interact to control sedimentary facies and what palaeoclimate indicators are reliable.
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13
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Abstract
The ascendancy of dinosaurs on land near the close of the Triassic now appears to have been as accidental and opportunistic as their demise and replacement by therian mammals at the end of the Cretaceous. The dinosaurian radiation, launched by 1-meter-long bipeds, was slower in tempo and more restricted in adaptive scope than that of therian mammals. A notable exception was the evolution of birds from small-bodied predatory dinosaurs, which involved a dramatic decrease in body size. Recurring phylogenetic trends among dinosaurs include, to the contrary, increase in body size. There is no evidence for co-evolution between predators and prey or between herbivores and flowering plants. As the major land masses drifted apart, dinosaurian biogeography was molded more by regional extinction and intercontinental dispersal than by the breakup sequence of Pangaea.
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Affiliation(s)
- P C Sereno
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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14
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Spray JG, Kelley SP, Rowley DB. Evidence for a late Triassic multiple impact event on Earth. Nature 1998. [DOI: 10.1038/32397] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Abstract
The ammonoid cephalopods range from the early Devonian to the late Cretaceous, a period of some 320 Ma. Because of their importance for biostratigraphic discrimination and their use in practical age dating for this period they have been intensively studied. Major extinctions at the close of the Devonian, end Permian, end Triassic and end Cretaceous have long been recognized and linked with regressional palaeogeographical events. The recognition of smaller-scale extinction events is relatively new and is especially well shown in the Palaeozoic, when there was a simpler distribution of land and sea pathways than in later periods when the influence of latitudinal distributions and local provinces was more severe. Extinction events in the Devonian show the nature of the process. Usually a gradual decline in diversity is followed by extinction; then there is a period of low diversity but often individual abundance. Then novelty appears and is seen in new characters of the early stages; elaboration and diversification follow. These fluctuations can often be correlated with changes in other groups and also with sedimentological and palaeogeographical changes. Usually a regression-transgression couplet is involved with evidence of ocean turnover indicated by anoxic or low-oxygen events. A new family, Sobolewiidae, is diagnosed. A new analysis of diversity, appearances and extinctions is made at the family level for 2 Ma time units throughout the history of the Ammonoidea. This record is compared with modern attempts to portray sea-level fluctuations and onlap and offlap movements of marine seas. The correlation, even in detail, is impressive and gives support for the species/area theory. But it is argued that temperature, as well as sea-level factors, is important. The evidence, on both large and small scales, shows an association of evolutionary change with palaeogeographical change. The new evidence does not suggest a role for periodicity above the Milankovitch Band level. Whether or not periodicity is involved, such factors seem more readily explained in endogenic earth causations and for the present these provide the most parsimonious explanations.
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16
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In the shadow of the Dinosaurs: Early mesozoic tetrapods. Trends Ecol Evol 1995. [DOI: 10.1016/s0169-5347(00)89143-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Catastrophe: impact of comets and asteroids. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0168-6321(06)80027-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Rogers RR, Swisher CC, Sereno PC, Monetta AM, Forster CA, Martínez RN. The Ischigualasto Tetrapod Assemblage (Late Triassic, Argentina) and 40Ar/39Ar Dating of Dinosaur Origins. Science 1993; 260:794-7. [PMID: 17746113 DOI: 10.1126/science.260.5109.794] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
(40)Ar/(39)Ar dating of sanidine from a bentonite interbedded in the Ischigualasto Formation of northwestern Argentina yielded a plateau age of 227.8 +/- 0.3 million years ago. This middle Carnian age is a direct calibration of the Ischigualasto tetrapod assemblage, which includes some of the best known early dinosaurs. This age shifts last appearances of Ischigualasto taxa back into the middle Carnian, diminishing the magnitude of the proposed late Carnian tetrapod extinction event. By 228 million years ago, the major dinosaurian lineages were established, and theropods were already important constituents of the carnivorous tetrapod guild in the Ischigualasto-Villa Unión Basin. Dinosaurs as a whole remained minor components of tetrapod faunas for at least another 10 million years.
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19
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Bice DM, Newton CR, McCauley S, Reiners PW, McRoberts CA. Shocked Quartz at the Triassic-Jurassic Boundary in Italy. Science 1992; 255:443-6. [PMID: 17842896 DOI: 10.1126/science.255.5043.443] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Quartz grains that appear to have been shock-metamorphosed occur within three closely spaced shale beds from the uppermost Triassic ("Rhaetian") Calcare a Rhaetavicula in the Northern Apennines of Italy. The upper shale coincides with the abrupt termination of the distinctive, uppermost Triassic Rhaetavicula fauna and is overlain by the Hettangian (Lower Jurassic) Calcare Massiccio; no extinctions appear to be associated with the two lower layers, which occur 1.2 and 2.4 meters below the boundary shale. Approximately 5 to 10% of the quartz grains within these layers exhibit one or more sets of planar deformational features whose orientations cluster around the rational crystallographic planes (basal, omega, and pi) most commonly observed in shocked quartz. Textural and stratigraphic observations support an interpretation of at least three closely spaced impacts at the end of the Triassic.
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20
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Benton MJ. Mass extinctions among tetrapods and the quality of the fossil record. Philos Trans R Soc Lond B Biol Sci 1989; 325:369-85; discussion 386. [PMID: 2574883 DOI: 10.1098/rstb.1989.0094] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The fossil record of tetrapods is very patchy because of the problems of preservation, in terrestrial sediments in particular, and because vertebrates are rarely very abundant. However, the fossil record of tetrapods has the advantages that it is easier to establish a phylogenetic taxonomy than for many invertebrate groups, and there is the potential for more detailed ecological analyses. The relative incompleteness of a fossil record may be assessed readily, and this can be used to test whether drops in overall diversity are related to mass extinctions or to gaps in our knowledge. Absolute incompleteness cannot be assessed directly, but a historical approach may offer clues to future improvements in our knowledge. One of the key problems facing palaeobiologists is paraphyly, the fact that many higher taxa in common use do not contain all of the descendants of the common ancestor. This may be overcome by cladistic analysis and the identification of monophyletic groups. The diversity of tetrapods increased from the Devonian to the Permian, remained roughly constant during the Mesozoic, and then began to increase in the late Cretaceous, and continued to do so during the Tertiary. The rapid radiation of 'modern' tetrapod groups--frogs, salamanders, lizards, snakes, turtles, crocodilians, birds and mammals--was hardly affected by the celebrated end-Cretaceous extinction event. Major mass extinctions among tetrapods took place in the early Permian, late Permian, early Triassic, late Triassic, late Cretaceous, early Oligocene and late Miocene. Many of these events appear to coincide with the major mass extinctions among marine invertebrates, but the tetrapod record is largely equivocal with regard to the theory of periodicity of mass extinctions.
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Affiliation(s)
- M J Benton
- Department of Geology, Queen's University of Belfast, U.K
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21
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Sepkoski JJ. Periodicity in extinction and the problem of catastrophism in the history of life. JOURNAL OF THE GEOLOGICAL SOCIETY 1989; 146:7-19. [PMID: 11539792 DOI: 10.1144/gsjgs.146.1.0007] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The hypothesis that extinction events have recurred periodically over the last quarter billion years is greatly strengthened by new data on the stratigraphic ranges of marine animal genera. In the interval from the Permian to Recent, these data encompass some 13,000 generic extinctions, providing a more sensitive indicator of species-level extinctions than previously used familial data. Extinction time series computed from the generic data display nine strong peaks that are nearly uniformly spaced at 26 Ma intervals over the last 270 Ma. Most of these peaks correspond to extinction events recognized in more detailed, if limited, biostratigraphic studies. These new data weaken or negate most arguments against periodicity, which have involved criticisms of the taxonomic data base, sampling intervals, chronometric time scales, and statistical methods used in previous analyses. The criticisms are reviewed in some detail and various new calculations and simulations, including one assessing the effects of paraphyletic taxa, are presented. Although the new data strengthen the case for periodicity, they offer little new insight into the deriving mechanism behind the pattern. However, they do suggest that many of the periodic events may not have been catastrophic, occurring instead over several stratigraphic stages or substages.
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Affiliation(s)
- J J Sepkoski
- Department of the Geophysical Sciences, University of Chicago, Illinois 60637, USA
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