[Taxacom] Molecular evidence (in 2017) supports my 2014 theory about rafting killifish

John Grehan calabar.john at gmail.com
Thu Dec 24 22:14:07 CST 2020


Ken, thanks for specifying that your support for their paper as evidence
comes from your acceptance of the time calibrated phylogeny in the article.
So naturally the question arises, as Heads stated, how was the time
calibrated? Costa et al say they use:

“a normal uncorrelated relaxed clock model, which emphasizes the minimum
age and has been considered appropriate for fossil calibration points”

OK that is fine, fossil calibration points are minimum dates. But (and
there is always a but in this stuff) they then say:

“A Yule speciation process for the tree prior (Gernhard, 2008) was used”

This 'prior was presented as follows:

“origin of the crown European cyprinodontoid clade (Pohl et al., 2015),
which was estimated to have occurred at least 33 Mya on the basis of the
oldest identifiable clade member”

“at least' is fine and factual, but then the oil gets applied with:

“prior setting: exponential distribution, mean = 33 and standard deviation
= 0.5).”

In other words, as if by magic, they have decided that the oldest upper
limit lies within a standard deviation of 0.5. Where on earth does this
come from? Well, not from earth as we know it. Its pure magic (I challenge
anyone to demonstrate otherwise). Its a sort of game – go on, pick a prior,
any prior will do. And all it produces is twaddle dressed up in fancy
algorithms and techniques.

Similarly for their second calibration point:

“where Aphanius and Valencia diverge, corresponding to the most ancient
record with recognisable synapomorphies of Aphanius, the fossil Aphanius …
with 17 Mya (prior setting: exponential distribution, mean = 17 and
standard deviation = 0.5.)

Same magic, same twaddle.

So when they say:

“Divergence time estimates indicate that the Neotropical aplocheiloid clade
diverged from its sister group comprising Old World aplocheiloids in the
Early Eocene (50 Mya, 95% HDP: 39–63 Mya).”

its really a sort of fraud as minimums are represented as a value with
maximum upper limits that are not much older. Its pure garbage, like
presenting lead as gold. A minimum is a minimum is a minimum. Twaddle,
twaddle, waddle all the day.

OK so I am rather blunt about it. But I have not seen any published
refutation of the empirical fact that fossils can only give mimiums with no
direct information on upper age limits of taxa and that molecular
extrapolations are in the same boat. Claims to the contrary therefore come
across as misrepresentations of the evidence, and misrepresentations are
fraudulent. Again, I am open to discussion with any expert on this list who
can present evidence to the contrary.

It appears that Ken believes in priors as authoritative when invoked by
molecular technologists and I have no problem with that. We are all
entitled to believe whatever we want. But in science one does look for an
empirical basis and it appears that Ken and others with the same viewpoint
cannot or are unwilling to give that – at least so far.

With respect Kryptolebias being capable of surviving out of water and
spending much of their time in logs and cavities of trees – that is fine as
an ecological quality. But it has no automatic connection with the origin
of allopatric taxa. Ironically it is biogeographic analysis that might give
some insight into understanding the role of ecological means of dispersal
rather than the other way around.

Taxacom might be the only place this issue is directly discussed. Good to
see. It's what makes Taxacom exceptional.

John Grehan



On Thu, Dec 24, 2020 at 9:35 AM Kenneth Kinman via Taxacom <
taxacom at mailman.nhm.ku.edu> wrote:

> Hi Jason,
>          Thanks for the input Jason.   Yes, the time calibrated phylogeny
> (from molecular sequences) in the article.  And also early-branching
> Kryptolebias known to be capable of surviving out of water for up to 66
> days and spending much of their time while out of the water in logs and
> cavities of trees (plenty of those in such rafts).  And I was even more
> convinced by their unusual reproductive abilities (hermaphroditism and even
> self-fertilization).  Seems like the best of all vertebrate candidates for
> trans-Atlantic dispersal in the Eocene-Oligocene time frame.
>                          --------------Ken
>
> ________________________________
> From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> on behalf of JF Mate
> via Taxacom <taxacom at mailman.nhm.ku.edu>
> Sent: Wednesday, December 23, 2020 10:54 PM
> To: John Grehan <calabar.john at gmail.com>; Taxacom <
> taxacom at mailman.nhm.ku.edu>
> Subject: Re: [Taxacom] Molecular evidence (in 2017) supports my 2014
> theory about rafting killifish
>
> I can't speak for Ken nor be sure that my interpretation is correct, but if
> I had to guess, then I would say that in the case of the killifish, the
> evidence for postvicariance dispersal would be in the time calibrated
> phylogeny and the pattern being consistent with previous studies detecting
> a similar pattern and timing. If am wrong in your interpretation Ken please
> let me know.
>
> Best and Merry Christmas to all
>
> Jason
>
> On Wed, 23 Dec 2020, 01:50 John Grehan, <calabar.john at gmail.com> wrote:
>
> > Jason,
> >
> > Thanks for the paper. I would be happy to do that, but first I need Ken
> to
> > specify what in the paper he sees as constituting evidence. Otherwise I
> am
> > just left guessing. Once Ken specifies what particular items presented in
> > the paper constitute evidence I would be happy to comment. I have noticed
> > that Ken tends to cite papers as evidence for is views, but rarely
> > specifies what within qualifies as evidence. I hope in this case he will
> do
> > that for the purposes of discussion.
> >
> > Cheers,
> >
> > John Grehan
> >
> > On Tue, Dec 22, 2020 at 9:37 AM JF Mate <aphodiinaemate at gmail.com>
> wrote:
> >
> >> Here is a copy John. Your line of argumention would be more constructive
> >> if you could provide a critique of their work and why you think their
> >> conclusions are wrong. That way it would be easier to understand your
> >> perspective.
> >>
> >> Best
> >>
> >> Jason
> >>
> >> On Tue, 22 Dec 2020, 07:07 John Grehan via Taxacom, <
> >> taxacom at mailman.nhm.ku.edu> wrote:
> >>
> >>> Hi Ken. See below
> >>>
> >>>  They say: "Our estimates indicate that divergence between the clades
> >>> comprising New World and Old World aplocheiloids occurred during the
> >>> Eocene, about 50 Mya, much more recent than the Gondwanan fragmentation
> >>> scenario assumed in previous studies."
> >>>
> >>> So they say. But what is the evidence? Ken, all you ever seem to do is
> >>> post
> >>> assertions, never specifying the evidence.
> >>>
> >>>  The molecular evidence in 2017 supports my theory.
> >>>
> >>> What is the molecular evidence?
> >>>
> >>> Cheers,
> >>>
> >>> John Grehan
> >>>
> >>>
> >>>
> >>> On Mon, Dec 21, 2020 at 3:40 PM Kenneth Kinman via Taxacom <
> >>> taxacom at mailman.nhm.ku.edu> wrote:
> >>>
> >>> > Hi All,
> >>> >       Rivulidae (a.k.a. Cynolebiini) are New World killifish once
> >>> thought
> >>> > to have arisen in the Cretaceous before South America fully separated
> >>> from
> >>> > Africa.  However, molecular evidence in 2017 indicates they arose in
> >>> the
> >>> > Eocene.   They say: "Our estimates indicate that divergence between
> the
> >>> > clades comprising New World and Old World aplocheiloids occurred
> >>> during the
> >>> > Eocene, about 50 Mya, much more recent than the Gondwanan
> fragmentation
> >>> > scenario assumed in previous studies. This estimation is nearly
> >>> synchronous
> >>> > to estimated splits involving other South American and African
> >>> vertebrate
> >>> > clades, which have been explained by transoceanic dispersal through
> an
> >>> > ancient Atlantic island chain during the Palaeogene."
> >>> >       This makes me quite happy since I brought up this possibility
> >>> back
> >>> > in 2014, in a post here on Taxacom entitled: transoceanic "rafting"
> >>> fish
> >>> > (great candidate).
> >>> >       The early branching genus Kryptolebias just happens to be a
> great
> >>> > candidate for a fish that could disperse on a raft of vegetation from
> >>> > Africa to South America:   (1) It's not only very tolerant of salt
> >>> water,
> >>> > but also and more importantly (2) it can survive out of water for
> >>> weeks at
> >>> > a time (66 days in one case).  (3) And guess where Kryptolebias
> >>> marmoratus
> >>> > spends much of its time while out of the water----in logs and
> cavities
> >>> of
> >>> > trees (which would be the main structural components of a large
> >>> > transoceanic raft).
> >>> >          Those are the three things I thought of offhand which
> pointed
> >>> to
> >>> > possible trans-Atlantic dispersal.  But then I began wondering about
> >>> yet
> >>> > another strange thing about Kryptolebias fish.  They often exhibit
> >>> various
> >>> > types of hermaphroditism, and even its most extreme form
> >>> > (self-fertilization, which is apparently absent in vertebrates except
> >>> for
> >>> > Kryptolebias).  So just a few of these fish (or even a single
> >>> individual)
> >>> > could have established a population on another continent.   The
> >>> molecular
> >>> > evidence in 2017 supports my theory.
> >>> >
> >>>
> https://www.sciencedirect.com/science/article/abs/pii/S1055790317300386?casa_token=ONKSbcnOLNEAAAAA:roWXxXgD1F0NqnWh9fozphZ4BbyAngOtCQwxXkyr552h7rNz1M366R2yniah-HK5hDFbRaaV
> >>> >
> >>> >                                   ------------------Ken
> >>> >
> >>> >
> >>> >
> >>>
> ----------------------------------------------------------------------------------------------------------------------------
> >>> >
> >>> >
> >>> > _______________________________________________
> >>> > 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 assaulting ambiguity for about 33 years,
> >>> 1987-2020.
> >>> >
> >>> _______________________________________________
> >>> 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 assaulting ambiguity for about 33 years,
> >>> 1987-2020.
> >>>
> >>
> _______________________________________________
> 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 assaulting ambiguity for about 33 years, 1987-2020.
> _______________________________________________
> 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 assaulting ambiguity for about 33 years, 1987-2020.
>


More information about the Taxacom mailing list