Constraints on clade ages from fossil outgroups

  title={Constraints on clade ages from fossil outgroups},
  author={Matthew M. Hedman},
  • M. Hedman
  • Published in Paleobiology 5 January 2010
  • Geography
Abstract This paper presents a method for constraining the age of a clade with the ages of the earliest fossil specimens in that clade's outgroups. Given a sufficiently deep, robust, well-resolved, and stratigraphically consistent cladogram, this method can yield useful age constraints even in the absence of specific information about the fossil preservation and recovery rates of individual taxa. The algorithm is applied to simulated data sets to demonstrate that this method can yield robust… 

Using the Fossil Record to Evaluate Timetree Timescales

  • C. Marshall
  • Geography, Environmental Science
    Front. Genet.
  • 2019
Five primary methods have been developed to estimate maximum age brackets and their relative magnitudes are reviewed, which typically correlate with the age of the group, its geographic range, and species richness.

Dating placentalia: Morphological clocks fail to close the molecular fossil gap

The results suggest that tip calibration may result in estimated dates that are more ancient than those obtained from other sources of data, and that results obtained using tip calibration, and possibly morphological dating more generally, should be treated with caution.

Exact distribution of divergence times from fossil ages and tree topologies

This work suggests an older age for Amniota (the synapsid/sauropsid or bird/mammal divergence) than has been assumed by most studies that have used this constraint and provides, for the first time, a method to compute the shape of the probability density for this divergence time.

Exact distribution of divergence times from fossil ages and tree topologies.

This work suggests an older age for Amniota (the synapsid/sauropsid or bird/mammal divergence) than has been assumed by most studies that have used this constraint and provides, for the first time, a method to compute the shape of the probability density for this divergence time.

Exploring the impact of fossil constraints on the divergence time estimates of derived liverworts

In this study, we evaluate the impact of fossil assignments and different models of calibration on divergence time estimates carried out as Bayesian analyses. Estimated ages from preceding studies

Tectonic blocks and molecular clocks

Biogeographic and fossil calibrations are complementary, not competing, approaches to constraining molecular clock analyses, providing alternative constraints on the age of clades that are vital to avoiding circularity in investigating the role of biogeographic mechanisms in shaping modern biodiversity.

Can We Reliably Calibrate Deep Nodes in the Tetrapod Tree? Case Studies in Deep Tetrapod Divergences

It is found that node priors for amphibians and tetrapods show high phylogenetic lability and different phylogenetic treatments identifying disparate taxa as the earliest representatives of these crown groups, and it is suggested that sampling outside of classic European and North American sections may dramatically change the timelines of tetrapod evolution.

Fossil data support a pre-Cretaceous origin of flowering plants.

A Bayesian method is developed to estimate the ages of angiosperm families on the basis of the fossil record (a newly compiled dataset of ~15,000 occurrences in 198 families) and their living diversity and indicates that several families originated in the Jurassic, strongly rejecting a Cretaceous origin for the group.

Bias in phylogenetic measurements of extinction and a case study of end‐Permian tetrapods

Here, simulations are used to investigate the adequacy of measures of phylogenetic clustering of extinction when applied to phylogenies of fossil taxa while assuming a Brownian motion model of trait evolution, and expected biases under a variety of evolutionary and analytical scenarios are characterized.

Best Practices for Justifying Fossil Calibrations

  • JamesF. Benton
  • Environmental Science
    Systematic biology
  • 2012
Our ability to correlate biological evolution with climate change, geological evolution, and other historical patterns is essential to understanding the processes that shape biodiversity. Combining



Using the fossil record to estimate the age of the last common ancestor of extant primates

A new statistical method is presented, based on an estimate of species preservation derived from a model of the diversification pattern, that suggests a Cretaceous last common ancestor of primates, approximately 81.5 Myr ago, close to the initial divergence time inferred from molecular data.

Stratigraphic tests of cladistic hypotheses

  • P. Wagner
  • Environmental Science
  • 1995
The results caution against evaluating phylogenetic hypotheses of fossil taxa without considering both stratigraphic data and the possible presence of ancestral species, as both factors can affect interpretations of a clade's evolutionary dynamics and its patterns of morphologic evolution.

A Simple Method for Bracketing Absolute Divergence Times on Molecular Phylogenies Using Multiple Fossil Calibration Points

A central challenge facing the temporal calibration of molecular phylogenies is finding a quantitative method for estimating maximum age constraints on lineage divergence times and this method, exploiting the fact that the relative branch lengths on the ultrametric tree are proportional to time is provided.

Maximum likelihood estimation of phylogeny using stratigraphic data

The method appears to perform well as a tree rooting criterion even when preservation rates are low, and several possible extensions are suggested to address other questions about the nature of fossil preservation and the process of speciation and extinction over time and space.

On fossil preservation and the stratigraphic ranges of taxa

Maximum likelihood estimation of mean taxonomic duration, fossil preservation rate, and completeness of the local fossil record under a model in which duration has an exponential distribution and the locations of preserved finds follow a Poisson process is described.

Quantitative Analysis of the Timing of the Origin and Diversification of Extant Placental Orders

Although the fossil record is incomplete, it appears adequate to reject the hypothesis that orders of placentals began to diversify before the K/T boundary; thus, early Tertiary ordinal diversification is real.

Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary

The discovery of a new well-preserved mammal from the Late Cretaceous of Mongolia and a broad-scale phylogenetic analysis that includes all well-known CRETaceous fossils and a wide sample of morphology among Tertiary and recent placentals are reported.

Inferring temporal patterns of preservation, origination, and extinction from taxonomic survivorship analysis

  • M. Foote
  • Environmental Science, Geography
  • 2001
An approach that can undo distortions and thus permit estimates of true taxonomic rates, while providing estimates of preservation in the process is presented, and preliminary application to data on Paleozoic marine animals suggests that some features of the apparent record can be detected and corrected.

Placental mammal diversification and the Cretaceous–Tertiary boundary

The largest available molecular data set for placental mammals is investigated, which includes segments of 19 nuclear and three mitochondrial genes for representatives of all extant placental orders and permits simultaneous constraints from the fossil record and allows rates of molecular evolution to vary on different branches of a phylogenetic tree.