Beyond the lower-bound: the fossil record can provide empirically-informed prior distributions

on node ages in poorly-sampled groups

Graeme T. Lloyd, Matt Friedman and Mark A. Bell

Credit/blame

Matt Friedman Mark Bell

When?

When?

When?

Olenekian

247.2

251.2

Prior distribution

247.2

Prior distribution

247.2

?

Fossil dating approaches #1

Nowak et al. 2013

Fossil dating approaches #2

Bapst in press

Time

Required data

TreeTip ages

Sampling rate

Branching rateExtinction rate

Extant diversity

Required data

TreeTip ages

Sampling rate

Branching rateExtinction rate

Extant diversity

Fossil dating approaches #3

τ6

τ5

τ4

τ2

τ1

τ3

Hedman 2010

τ0

Fossil dating approaches #3

τ0

τ6

τ5

τ4

τ2

τ1

τ3

Hedman 2010Age (Ma)

τ0

Problem

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τ5

τ4

τ2

τ1

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τ0

Hedman 2010

Solution #1

τ6

τ5

τ4

τ2

τ1

τ3

τ0

Hedman 2010

Solution #2

τ6

τ5

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τ2

τ1

τ3

τ0

Hedman 2010

Solution #2

τ6

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τ2

τ1

τ3

τ0

Hedman 2010

=

Frequency of problem

Lloyd et al. 2008

135/416 ‘unique’ nodes

Frequency of problem

135/416 ‘unique’ nodes

What about the other two thirds?

Lloyd et al. 2008

Modified approach

Modified approach

Modified approach

12

3

Modified approach

12

3

Min Max

Modified approach

1 2 3

12

3

Min Max

Modified approach

12

3

Data

• Informal supertree• Molecular backbone• 29 source trees• 567 taxa (483 fossil)• c. 10 minutes

Dated tree

Testing t0

Testing t0

Cambrian vs. Jurassic t0: Median

Cambrian vs. Jurassic t0: Mean

Cambrian vs. Jurassic t0: L95%

Cambrian vs. Jurassic t0: U95%

Molecular divergences #1

Meredith et al. 2011

Molecular divergences #2

dos Reis et al. 2012

Molecular comparison

This study Meredithet al. 2011

dos Reiset al. 2012

This study -

Meredithet al. 2011 1.07-1.17 -

dos Reiset al. 2012 1.00-1.09 1.00-1.16 -

Molecular comparisonTh

is st

udy

Meredith et al. 2011 dos Reis et al. 2012

Conclusions

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τ0

Conclusions

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Conclusions