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Journal ArticleDOI

The age of the Cretaceous Santana Formation fossil Konservat Lagerstätte of north-east Brazil: a historical review and an appraisal of the biochronostratigraphic utility of its palaeobiota

01 Dec 2007-Cretaceous Research (Academic Press Inc.)-Vol. 28, Iss: 6, pp 895-920
TL;DR: In the case of the Romualdo Member of the Santana Formation Konservat Lagerstatten of north-east Brazil, it was first dated as Cretaceous by Agassiz on the basis of fish fossils obtained by Bavarian explorers Spix and Martius between 1817 and 1820 as discussed by the authors.
About: This article is published in Cretaceous Research.The article was published on 2007-12-01. It has received 106 citations till now. The article focuses on the topics: Santana Formation & Aptian.
Citations
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Journal ArticleDOI
TL;DR: A timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte−tracheophyte relationships, among other variables, on divergence time estimation is established.
Abstract: Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth's System. The sparseness of early land plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte-tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for Viridiplantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within Viridiplantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian-Early Ordovician, origin.

573 citations

Journal ArticleDOI
TL;DR: A post-Jurassic origin of angiosperms and a post-Cambrian origin of land plants are rejected, and it is suggested that the establishment of the major embryophyte lineages occurred at a much slower tempo than suggested in most previous studies.
Abstract: • Plants have utterly transformed the planet, but testing hypotheses of causality requires a reliable time-scale for plant evolution. While clock methods have been extensively developed, less attention has been paid to the correct interpretation and appropriate implementation of fossil data. • We constructed 17 calibrations, consisting of minimum constraints and soft maximum constraints, for divergences between model representatives of the major land plant lineages. Using a data set of seven plastid genes, we performed a cross-validation analysis to determine the consistency of the calibrations. Six molecular clock analyses were then conducted, one with the original calibrations, and others exploring the impact on divergence estimates of changing maxima at basal nodes, and prior probability densities within calibrations. • Cross-validation highlighted Tracheophyta and Euphyllophyta calibrations as inconsistent, either because their soft maxima were overly conservative or because of undetected rate variation. Molecular clock analyses yielded estimates ranging from 568-815 million yr before present (Ma) for crown embryophytes and from 175-240 Ma for crown angiosperms. • We reject both a post-Jurassic origin of angiosperms and a post-Cambrian origin of land plants. Our analyses also suggest that the establishment of the major embryophyte lineages occurred at a much slower tempo than suggested in most previous studies. These conclusions are entirely compatible with current palaeobotanical data, although not necessarily with their interpretation by palaeobotanists.

327 citations


Cites background from "The age of the Cretaceous Santana F..."

  • ...The Crato Formation, part of the Santana Group (sensu Neumann & Cabrera, 1999), is considered to be Late Aptian– Early Albian on the basis of pollen (Batten, 2007) ostracod (Martill, 2007) and dinoflagellate (Heimhofer & Hochuli, 2010) biostratigraphy....

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Journal ArticleDOI
TL;DR: A series of rigorously vetted calibration fossils for arthropod evolutionary history, taking into account recently published guidelines for best practice in fossil calibration are presented, resulting in 80 fossil calibrations for 102 clades.

159 citations

Journal ArticleDOI
TL;DR: A Bayesian molecular dating method is used to analyse a dataset of 83 genes from 644 taxa and 52 fossil calibrations to explore the effect of different interpretations of the fossil record, molecular clock models, data partitioning, among other factors, on angiosperm divergence time estimation, and indicates that the timescale of angiosperms diversification is much less certain than previous molecular dating studies have suggested.
Abstract: Through the lens of the fossil record, angiosperm diversification precipitated a Cretaceous Terrestrial Revolution (KTR) in which pollinators, herbivores and predators underwent explosive co‐diversification. Molecular dating studies imply that early angiosperm evolution is not documented in the fossil record. This mismatch remains controversial. / We used a Bayesian molecular dating method to analyse a dataset of 83 genes from 644 taxa and 52 fossil calibrations to explore the effect of different interpretations of the fossil record, molecular clock models, data partitioning, among other factors, on angiosperm divergence time estimation. / Controlling for different sources of uncertainty indicates that the timescale of angiosperm diversification is much less certain than previous molecular dating studies have suggested. Discord between molecular clock and purely fossil‐based interpretations of angiosperm diversification may be a consequence of false precision on both sides. / We reject a post‐Jurassic origin of angiosperms, supporting the notion of a cryptic early history of angiosperms, but this history may be as much as 121 Myr, or as little as 23 Myr. These conclusions remain compatible with palaeobotanical evidence and a more general KTR in which major groups of angiosperms diverged later within the Cretaceous, alongside the diversification of pollinators, herbivores and their predators.

141 citations

Journal ArticleDOI
TL;DR: This work provides the first explicitly justified minimum and soft maximum age constraints on 22 clades of turtles following best practice protocols and generates novel age-of-origination estimates for clades within crown Testudines.
Abstract: Turtles have served as a model system for molecular divergence dating studies using fossil calibrations. However, because some parts of the fossil record of turtles are very well known, divergence age estimates from molecular phylogenies often do not differ greatly from those observed directly from the fossil record alone. Also, the phylogenetic position and age of turtle fossil calibrations used in previous studies have not been adequately justified. We provide the first explicitly justified minimum and soft maximum age constraints on 22 clades of turtles following best practice protocols. Using these data we undertook a Bayesian relaxed molecular clock analysis establishing a timescale for the evolution of crown Testudines that we exploit in attempting to address evolutionary questions that cannot be resolved with fossils alone. Some of these questions, such as whether the turtle crown originated in the Triassic or Jurassic, cannot be resolved by our analysis. However, our results generate novel age-of-origination estimates for clades within crown Testudines. Finally, we compare our fossil calibrations and posterior age estimates to those from other studies, revealing substantial differences in results and interpretation.

141 citations


Cites background or methods from "The age of the Cretaceous Santana F..."

  • ...Older fossils from Asia have been assigned to the stem of Testudinoidea, including fragmentary fossils from the Barremian (.125.0 Ma) of Japan (Hirayama, 2002) and the Albian/ Cenomanian (.92.4 Ma) of Uzbekistan (Danilov, 1999)....

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  • ...The youngest possible age for the Santana Group is Cenomanian (Martill, 2007) and we therefore use the top of the Cenomanian for our minimum at 92....

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  • ...Older specimens from the Cenomanian– Turonian of Mongolia previously referred to Hoplochelys sp. are now identified as ‘‘macrobaenids’’ (Sukhanov et al., 2008)....

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  • ...The youngest possible age for the Santana Group is Cenomanian (Martill, 2007) and we therefore use the top of the Cenomanian for our minimum at 92.8 Ma (93.6 6 0.8 Ma; Gradstein et al., 2004; Ogg et al., 2008)....

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  • ...As spectacular as the fossils are from the Santana Group, the stratigraphic sequence remains poorly dated to somewhere around the Early/Late Cretaceous (e.g., Maisey, 1990; Fara et al., 2005; Martill, 2007)....

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References
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Journal ArticleDOI
06 Mar 1987-Science
TL;DR: An effort has been made to develop a realistic and accurate time scale and widely applicablechronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework.
Abstract: Advances in sequence stratigraphy and the development of depositional models have helped explain the origin of genetically related sedimentary packages during sea level cycles. These concepts have provided the basis for the recognition of sea level events in subsurface data and in outcrops of marine sediments around the world. Knowledge of these events has led to a new generation of Mesozoic and Cenozoic global cycle charts that chronicle the history of sea level fluctuations during the past 250 million years in greater detail than was possible from seismic-stratigraphic data alone. An effort has been made to develop a realistic and accurate time scale and widely applicable chronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework. A description of this approach and an account of the results, illustrated by sea level cycle charts of the Cenozoic, Cretaceous, Jurassic, and Triassic intervals, are presented.

6,928 citations

Journal Article
TL;DR: In this article, an interpretation of these events as the result of the interplay of two major geologic and climatic factors is given, namely, the Late Cretaceous transgression which increased the area and volume of shallow epicontinental and marginal seas and was accompanied by an increase in the production of organic carbon; and the existence of an equable global climate which reduced the supply of cold oxygenated bottom water to the world ocean.
Abstract: Organic carbon-rich sediments are globally developed in pelagic sedimentary sequences of Aptian-Albian and Cenomanian-Turonian age. They formed in a variety of paleo-bathymetric settings including oceanic plateaus and basins, continental margins and shelf seas. The widespread nature of these deposits suggests that they were not strictly controlled by local basin geometry but were a product of ″Oceanic Anoxic Events″ . Interpretation of these events as the result of the interplay of two major geologic and climatic factors is given. The Late Cretaceous transgression which increased the area and volume of shallow epicontinental and marginal seas and was accompanied by an increase in the production of organic carbon; and the existence of an equable global climate which reduced the supply of cold oxygenated bottom water to the world ocean. This combination of climatic and hypsographic conditions favoured the formation of an expanded oxygen-minimum layer and where this intersected the sediment-water interface, organic carbon-rich deposits could be formed, these being records of ″Oceanic Anoxic Events″ .

1,420 citations

Book
01 Jan 1833

623 citations

Journal ArticleDOI
TL;DR: The Cenomanian-Turonian Oceanic Anoxic Event (OAE) as discussed by the authors was a short-lived episode of oceanic oxygen deficiency that occurred between 90.5 and 91.5 million years ago.
Abstract: Marine strata deposited during late Cenomanian and early Turonian time display lithological, faunal, and geochemical characteristics which indicate that significant parts of the world ocean were periodically oxygen deficient. At, or very close to, the Cenomanian-Turonian boundary, between 90.5 and 91.5Ma ago, oxygen deficiencies were particularly marked over a period of <1Ma. This short-lived episode of oceanic oxygen deficiency has been termed the Cenomanian-Turonian 'Oceanic Anoxic Event' (OAE). The widespread distribution of anoxic sediments deposited synchronously during such a short-lived event indicates that such sediments are not simply the product of coincidental local climatic or basinal water mass characteristics but are the result of a global expansion and intensification of the Cenomanian-Turonian oxygen-minimum zone related to feedback between sea level rise and regional palaeoceanography. The palaeoceanography of the Cenomanian Turonian OAE is discussed in detail in a companion paper by Arthur et al, 1987.-from Authors

567 citations