[Taxacom] Taxacom Digest, Vol 185, Issue 14

Mon Sep 20 09:34:15 CDT 2021

Hi Brendon,

Mike is probably right that it is not 'guessing' in the sense of just
making up any age, but my point is that transforming a given fossil record
into a prediction of the upper age of a taxon is problematic to say the
least. I have seen studies of the fossil records where it is argued that
for a given fossil range being over a 'sufficient' range of geological
horizons and 'sufficient' number of samples, that fossil range is supposed
to be predictive of the age of origin, but how that is necessarily so is
still beyond me. In other words, the date ranges are not in any empirical
way a necessary correlate of the upper age limit of a taxon.

“What is it that most authors do when they claim refutation of tectonic
correlation? I am not sure I follow this thought.”

They propose various chance dispersal scenarios. In other words, if their
fossil calibrated molecular age postdates a tectonic event, that event is
considered too early to be relevant. If there is a distributional gap
involved they then invoke chance dispersal. This argument is invalid since
the fossils provide minimum ages and so the molecular extrapolation is also
a minimum that does not falsify earlier origins.

“ I am not sure about the statement that many extant species have a
Mesozoic origin”

I did not say may, but I have found some examples of ghost moths with
Mesozoic tectonic boundaries.

So, to clarify for the purposes of discussion, do you accept that using
your dating methods that a taxon could still be older than that estimated
and therefore a given range estimate based on posterior probabilities has
nothing to do with how old a taxon may actually be and that a tectonic
correlation supporting an older origin is not falsified?

Cheers, John

On Mon, Sep 20, 2021 at 9:06 AM Brendon E. Boudinot via Taxacom <
taxacom at mailman.nhm.ku.edu> wrote:

> Hello John and Michael!
>
> Below are my thoughts. Your text is set in italics to differentiate from my
> responses.
>
> Cheers!
> Brendon
>
> *Hi Brendon,  *
>
>
>
> *Great to have your comment and viewpoint. Taken in a non-combative spirit
> as always. When you say you disagree, I presume you are disagreeing with my
> assertion that priors are just guesses. At this point your description does
> not help me see anything to the contrary. You say that you "set my fossil
> priors as the evidence-based stratigraphic range for the given deposit or
> formation." So what does that really mean? *
>
> That means that I do not enter an arbitrary guess for the age of a fossil.
> For example, if I were to conduct a tip-dating (“total-evidence”)
> phylogenetic analysis of the Dolichoderinae, I would want to include
> †*Azteca
> alpha*, from Dominican ambers. I do not enter “Azteca_alpha (100, 90)” or
> “Azteca_alpha (65, 20)” or “Azteca_alpha (65, 0)”, as these would indeed be
> guesses. Rather, I consider the set of studies which have evaluated the
> possible age range of the Dominican formations and choose the age range
> which is best supported. I would not set “Azteca_alpha (45, 40)”, the NMRS
> estimate of Lambert, Frye, and Poinar (1985, *Archaeometry*, 27, 43),
> because this study employed only two points to for their age calibration
> curve. I would choose instead “Azteca_alpha (20, 15)”, based on the
> multiple lines of corroborating evidence provided by Itteralde-Vinent and
> MacPhee (1996, *Science*, 273, 1850–1852). If I were concerned about the
> conflicting ages, I could enter “Azteca_alpha (45,15)” and evaluate the
> possible effects this has on the posterior distribution of trees. A final
> alternative is to just use “Azteca_alpha (15)” to say that the minimum age
> for the fossil is 15 million years, although I would prefer to use date
> ranges.
>
>
>
> *I actually have no problem with anyone assigning priors on how much older
> than the oldest fossil they think a taxon might be, or even making up
> probabilities for that. The problem arises when these are transformed into
> empirical limits that are supposed to falsify earlier origins predicted
> from tectonic correlation (for example). Also, the means of the priors are
> very often presented as actual ages so that taxa are said to have
> originated at (or about) such and such a date (and precluding earlier
> tectonically mediated origins). *
>
> When used as node calibrations, the lognormal and normal distributions
> allow the analysis to estimate ages which are effectively infinitely old
> for that given node. If the data are informative, the posterior estimate
> for the node’s age will narrow, thus more incisive for hypothesis testing;
> if the data are uninformative, the posterior range will be broad. I would
> not use a prior to falsify a hypothesis; such a construction is an invalid
> hypothesis test. The test can be done through the comparison of model fit
> or log likelihood across multiple analyses, with the caveat that there are
> no final answers. The hypothesis testing is done with the posterior
> estimates, not the priors.
>
>
>
> *I had one colleague note to me that one of the probability models (might
> be long normal, not sure) did not set an upper limit on the possibilities,
> yet in practice that is what most authors do when they say they refute
> earlier origins predicted by tectonic correlation. *
>
> What is it that most authors do when they claim refutation of tectonic
> correlation? I am not sure I follow this thought.
>
>
>
> *I might have less of an issue if priors were presented in the form of a
> probability that the oldest age, or even the mean age, was AT LEAST such
> and such age. *
>
> Priors set for fossil ages in the tip-dating framework are effectively
> statements of “this fossil is approximately X years old”. The priors of
> fossil ages are just one set of parameters in the analysis, which are then
> used to estimate the branch lengths given the available evidence. Once a
> Bayesian analysis is run, one receives a range of posterior probabilities,
> for which the only statistically honest way to present them are as ranges.
> The interpretation from there can vary and should be justified.
>
>
>
> *One might take the view that priors make Mesozoic origins for extant taxa,
> even species or genera, very ‘improbable’, but that is not the same as
> impossible, and heck, there are an awful lot of Mesozoic (not to mention
> Cenozoic) tectonic correlations. *
>
> Setting a prior on a node itself based on the minimum age of a fossil of
> presumed relationship is “node calibration”, and can have several
> distributions, most of which have infinite tails. I am not sure about the
> statement that many extant species have a Mesozoic origin. There is no
> direct or indirect evidence, for example, that socially parasitic ant
> species which render their host species paraphyletic are > 65 million years
> old.
>
>
>
> *To attribute that all to ‘chance’ coincidence (which would seem to be the
> only explanation) is hardly productive. It’s kind of like saying that God
> only made all the evidence of Creation only look like evolution occurred.*
>
> I am not sure about this statement. Stochastic events can have critical
> effects on populations or sets of populations.
>
>
>
> *Cheers, John*
>
>
>
> *Hi Brendon,*
>
>
>
> *You say 'I set my fossil priors as the evidence-based stratigraphic range
> for the given deposit or formation'.*
>
>
>
> *That is, if the fossil is in a formation dated as extending from 10-20 Ma,
> the group can be no older than 20 Ma. But why not? I don't see that the age
> of the formation is relevant. It's like saying that if a fossil is in the
> Cenozoic, it's group can't be Mesozoic, because that's a separate era. .*
>
> I did not state that a group cannot be older than the oldest estimated age
> for a given fossil deposit. The age of a fossil’s formation is relevant
> when one is conducting tip-dating (“combined-evidence”) analysis, which
> incorporates the ages of the given fossils themselves in the estimation of
> the age distributions of the tree. In these analyses, the placement of the
> fossil is allowed to vary and is informed by the morphological data. One
> can choose to use node calibrations in tip-dating analysis or not. In
> tip-dating analysis
>
>
>
> *You're right, this technique ('bounding') isn't guesswork, but it seems
> arbitrary and illogical. Why not just say that, based on the fossil record,
> the fossil's group is older than the fossil by some unknown amount? This is
> a valid and useful contribution, and data from other fields (e.g.
> biogeography) can then be used to investigate further. I don't think you
> can assess the accuracy of the fossil record by using data from the same
> record.  *
>
> One should indeed expect that the age of a fossil group is older than the
> oldest crown fossil of that group. It is precisely the age information of
> the fossil which is used to estimate a range of dates for nodes of the
> tree. The question of fossil record accuracy is distinct from the use of
> the phenotypic and stratigraphic data from a sample of fossils for
> phylogenetic analysis.
>
>
>
> *Biogeographic-tectonic calibration  is now used quite widely (e.g. Ho et
> al., 2015; De Baets et al., 2016; Landis, 2017; Gunter et al., 2018, Pett &
> Heath, 2020).  As Landis (2020) argued, ‘Fossil and biogeographic dating
> methods… should be regarded as complementary, not competing, strategies’.
> This is the synthetic approach we take, using fossil-calibrated ages as
> estimates of minimum clade age and biogeographic-tectonic calibrations as
> estimates of actual clade age.  *
>
> I have no comment for the use of tectonic splits in biogeographic analysis,
> except to note that I do not think that plate tectonics influences the
> evolution of socially parasitic ants of the Colorado plateau.
>
>
>
> On Sun, Sep 19, 2021 at 9:51 PM Michael Heads <m.j.heads at gmail.com> wrote:
>
> > Hi Brendon,
> >
> > You say 'I set my fossil priors as the evidence-based stratigraphic range
> > for the given deposit or formation'.
> >
> > That is, if the fossil is in a formation dated as extending from 10-20
> Ma,
> > the group can be no older than 20 Ma. But why not? I don't see that the
> age
> > of the formation is relevant. It's like saying that if a fossil is in the
> > Cenozoic, it's group can't be Mesozoic, because that's a separate era. .
> >
> > You're right, this technique ('bounding') isn't guesswork, but it seems
> > arbitrary and illogical. Why not just say that, based on the fossil
> record,
> > the fossil's group is *older than* the fossil by some unknown amount?
> > This is a valid and useful contribution, and data from other fields (e.g.
> > biogeography) can then be used to investigate further. I don't think you
> > can assess the accuracy of the fossil record by using data from the same
> > record.
> >
> > Biogeographic-tectonic calibration  is now used quite widely (e.g. Ho et
> > al., 2015; De Baets et al., 2016; Landis, 2017; Gunter et al., 2018,
> Pett &
> > Heath, 2020).  As Landis (2020) argued, ‘Fossil and biogeographic dating
> > methods… should be regarded as complementary, not competing, strategies’.
> > This is the synthetic approach we take, using fossil-calibrated ages as
> > estimates of minimum clade age and biogeographic-tectonic calibrations as
> > estimates of actual clade age.
> >
> > On Mon, Sep 20, 2021 at 3:52 AM Brendon E. Boudinot via Taxacom <
> > taxacom at mailman.nhm.ku.edu> wrote:
> >
> >> Hello John!
> >>
> >> I disagree. In tip-dating analyses, I set my fossil priors as the
> >> evidence-based stratigraphic range for the given deposit or formation.
> >> Using this range, we can account for patterns of variation for both
> >> morphology and molecular data, given the estimated range of possible
> >> relationships and clades ages. The priors have strong affect when there
> is
> >> little information, such as at a root node. The main point is accounting
> >> for uncertainty regarding the most recent or oldest possible age for a
> >> fossil. Please explain, in this context, why that is a problem. I am
> here
> >> today because of curiosity in general; likewise, I am responding now
> >> because of specific curiosity. What alternatives should one make use of
> to
> >> combine genotypic, phenotypic, and stratigraphic ranges for estimating a
> >> possible set of relationships and ages?
> >>
> >> Noncombatively,
> >> Brendon
> >>
> >> On Sat, 18 Sep 2021, 19:05 <taxacom-request at mailman.nhm.ku.edu> wrote:
> >>
> >> > Daily News from the Taxacom Mailing List
> >> >
> >> > When responding to a message, please do not copy the entire digest
> into
> >> > your reply.
> >> > ____________________________________
> >> >
> >> >
> >> > Today's Topics:
> >> >
> >> >    1. Re: Snake garbage (John Grehan)
> >> >
> >> >
> >> > ----------------------------------------------------------------------
> >> >
> >> > Message: 1
> >> > Date: Fri, 17 Sep 2021 16:25:36 -0400
> >> > From: John Grehan <calabar.john at gmail.com>
> >> > To: taxacom <taxacom at mailman.nhm.ku.edu>
> >> > Subject: Re: [Taxacom] Snake garbage
> >> > Message-ID:
> >> >         <CADN0ud1-28JXFunp23V6=
> >> > v4evN7orEypWnxjf04t+TGoES5bEQ at mail.gmail.com>
> >> > Content-Type: text/plain; charset="UTF-8"
> >> >
> >> > I wrote the original note in a bit of a hurry (should not do that) and
> >> > quite justifiably got castigated off list for not making sense. So
> >> below a
> >> > hopefully more coherent rant.
> >> >
> >> > This paper carries on the time honored scientific tradition of just
> >> > ignoring shortcomings of a method and ploughing on as if the ground
> was
> >> not
> >> > already falling away beneath. In this case the paper does this by
> >> > representing priors as some kind of empirically real source of
> >> estimating
> >> > fossil calibrated clade ages whereas it has been shown that fossil
> >> > calibrated ages cannot be anything but a minimum ages. Priors are just
> >> > personal guesses about how much older than the older fossil a taxon
> >> might
> >> > be (dressed up in numbers to look scientific). These authors just
> ignore
> >> > that. And they continue the temptation of using an automated
> >> biogeography
> >> > program as 'evidence' despite its inherent inability to distinguish
> >> between
> >> > vicariance and dispersal where either can generate the same
> >> biogeographic
> >> > pattern. In other words, they use a plug and play program that can
> >> render
> >> > artificial results and they have no way to know. But the authors carry
> >> on
> >> > the pretense that this is not the case.
> >> >
> >> > Cheers, John
> >> >
> >> > On Fri, Sep 17, 2021 at 10:20 AM John Grehan <calabar.john at gmail.com>
> >> > wrote:
> >> >
> >> > > "Evolution and dispersal of snakes across the Cretaceous-Paleogene
> >> mass
> >> > > extinction" (https://www.nature.com/articles/s41467-021-25136-y.pdf
> )
> >> > >
> >> > > This paper carries on the time honored scientific tradition of just
> >> > > ignoring shortcomings of a method and ploughing on as if the ground
> >> was
> >> > not
> >> > > already falling away beneath. In this case the representation or
> >> priors
> >> > as
> >> > > some kind of empirically real source of estimating fossil calibrated
> >> > clade
> >> > > ages as anything but a minimum ages, and the continued temptation of
> >> > using
> >> > > an automated biogeography program as 'evidence' despite its
> >> > > inherent inability to distinguish between vicariance and dispersal
> >> where
> >> > > either can generate the same biogeographic pattern. I have been
> >> attacked
> >> > > for calling this stuff 'garbage' but I have not come up with a more
> >> > > accurate term - yet.
> >> > >
> >> > > John Grehan
> >> > >
> >> >
> >> >
> >> > ------------------------------
> >> >
> >> > Subject: Digest Footer
> >> >
> >> > Taxacom Mailing List
> >> >
> >> > Send Taxacom mailing list submissions to taxacom at mailman.nhm.ku.edu
> >> > For list information; to subscribe or unsubscribe, visit:
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> >> > You can reach the person managing the list at:
> >> > taxacom-owner at mailman.nhm.ku.edu
> >> > The Taxacom email archive back to 1992 can be searched at:
> >> > http://taxacom.markmail.org
> >> >
> >> > Nurturing nuance while assailing ambiguity for about 34 years,
> >> 1987-2021.
> >> >
> >> >
> >> > ------------------------------
> >> >
> >> > End of Taxacom Digest, Vol 185, Issue 14
> >> > ****************************************
> >> >
> >> _______________________________________________
> >> Taxacom Mailing List
> >>
> >> Send Taxacom mailing list submissions to: taxacom at mailman.nhm.ku.edu
> >> For list information; to subscribe or unsubscribe, visit:
> >> http://mailman.nhm.ku.edu/cgi-bin/mailman/listinfo/taxacom
> >> You can reach the person managing the list at:
> >> taxacom-owner at mailman.nhm.ku.edu
> >> The Taxacom email archive back to 1992 can be searched at:
> >> http://taxacom.markmail.org
> >>
> >> Nurturing nuance while assailing ambiguity for about 34 years,
> 1987-2021.
> >>
> >
> >
> > --
> > Dunedin, New Zealand.
> >
> > My books:
> >
> > *Biogeography and evolution in New Zealand. *Taylor and Francis/CRC, Boca
> > Raton FL. 2017.
> >
> https://www.routledge.com/Biogeography-and-Evolution-in-New-Zealand/Heads/p/book/9781498751872
> >
> >
> > *Biogeography of Australasia:  A molecular analysis*. Cambridge
> > University Press, Cambridge. 2014. www.cambridge.org/9781107041028
> >
> >
> > *Molecular panbiogeography of the tropics. *University of California
> > Press, Berkeley. 2012. www.ucpress.edu/book.php?isbn=9780520271968
> >
> >
> > *Panbiogeography: Tracking the history of life*. Oxford University Press,
> > New York. 1999. (With R. Craw and J. Grehan).
> > http://books.google.co.nz/books?id=Bm0_QQ3Z6GUC
> > <
> http://books.google.co.nz/books?id=Bm0_QQ3Z6GUC&dq=panbiogeography&source=gbs_navlinks_s
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
> --
> Dr. Brendon E. Boudinot
> Alexander von Humboldt Research Fellow
> Friedrich-Schiller-Universität Jena
> Institut für Zoologie und Evolutionsforschung
> Erbertstraße 1
> 07443 Jena DE
> _______________________________________________
> Taxacom Mailing List
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> The Taxacom email archive back to 1992 can be searched at:
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>
> Nurturing nuance while assailing ambiguity for about 34 years, 1987-2021.
>