[Taxacom] Jurassic primates???
Scott Thomson
scott.thomson321 at gmail.com
Wed Jun 13 21:59:19 CDT 2018
I think it is an interesting, and difficult issue. There is I think a point
where your "ghost" lineage is just too long to be credible based on current
knowledge. Then there are some where the only explanation is a ghost
lineage of immense length. What I do, with the turtles my specialty, is to
examine all the fossils including more distant relatives, what I find is
that although the direct linneage I am interested in may not exist, there
are relatives of it in the fossil record (I am not talking about direct
ancestors here but parallel lineages that probably split off somewhere in
the past from my interest group) that somewhat line up. What I am getting
at is there is evidence enough that makes a date feasible. Not correct,
just possible. Whereas in other groups there is nothing, and to me that
means something is likely wrong.
To use your example with the primates, and please these are not my
specialty, Are there any mammal fossils that would indicate this as
remotely possible. My recollection is there is not. From what I recall
mammals diversified into their modern counterparts around 60 mya, those
mammals from before hand were very primative. I could believe Cretaceous I
imagine they had to be there, but Jurassic is a long time for mammals. I
also think that there are geological events that matter in the explanations
of all this. For example, in dealing with the Chelid turtles I have to
explain the connection between South America and Australia. Where the
extant specimens live. The oldest fossils in Australia are about 103 mya,
the oldest in South America about 135 mya. the final split between
Australia, Antarctica and South America is at 106 mya so the divergence
between the south american and australian radiations seems to be in that
zone, ie 103-106 mya. Best I have so far. Chelid turtles cannot cope with
salt water any crossings were land or freshwater only.
In other words what I am getting at is you cannot just go by one line of
evidence, or one theory. Need to line all of them up, look at all the
fossils, all the molecular divergences and start doing the maths.
Interesting discussion
Cheers Scott
On Wed, Jun 13, 2018 at 10:29 PM, John Grehan <calabar.john at gmail.com>
wrote:
> Not to prejudge what Heads might say on this, but Ken points to a really
> interesting anomaly and one that should receive attention rather than being
> suppressed (as proposed by various biogeographic ‘authorities’). The
> anomaly is what Ken says – that there is a difference between the
> biogeographic prediction and the oldest fossils. The scientific interest
> here lies not in that there is a difference (after all there are many cases
> where molecular divergences predate the oldest fossils of taxa), but how
> does one empirically judge whether the difference it too large to be
> seriously considered. I think this is a very credible question and not one
> that I have seen (that I can recall) being properly discussed by skeptics
> for origins older than fossils. It’s clearly an interesting problem. How
> much older becomes incredible? How many millions of years? So for primates
> an age that is triple the ‘generally accepted age’ is seen to be
> problematic. What if it were just double? What if it were a bit less than
> that? The problem here is that there seems to be no objective criterion and
> so it comes down to personal judgment that itself carries no scientific
> merit.
>
> So for me I have seen the biogeographic patterns and tectonic correlations
> which point to an age substantially older than the oldest fossils. It could
> be that all these biogeographic matches are pure coincidence and actually
> mean nothing (just like Creationists want to believe that God made it look
> like evolution occurred when in fact it did not). That is an alternative,
> but not one that I have yet seen argued other than by personal belief.
> There is the case of angiosperms that are the sister taxa to some
> gymnosperms which means that they have a shared evolutionary age, but this
> goes back much further in the gymnosperms – Triassic vs early Cretaceous
> for angiosperms (assuming that is still the case). So what to do?Definitely
> an interesting question for evolutionary biology. It would be interesting
> for an editor of a major journal to invite the different viewpoints to lay
> out their evidence and interpretations as I am sure many would find that
> interesting to read.
>
> I don’t mind if anyone calls the much older origins fairy tales or not (and
> panbiogeography has been characterized in much worse ways anyway). More
> interested in how the evidence is argued. I call dispersal narratives fairy
> tales because they are not empirically grounded (not generated from
> evidence), but rather just invoked or imagined. It’s the same for selection
> stories to ‘explain’ the origin of ‘adaptations’. At least the
> panbiogeographic stories (all scientific explanations are stories) are
> generated from an interpretation of evidence indicating a historical
> relationship between geological and biological events.
>
> What’s the point of asking if anyone agrees with panbiogeographic
> perspectives on primates? Does belief determine reality the way it did for
> Baldwin and Chamberlain? And we all know what happened to that.
>
> Cheers, John Grehan
>
>
> On Wed, Jun 13, 2018 at 9:50 PM, Kenneth Kinman <kinman at hotmail.com>
> wrote:
>
> > Michael,
> >
> > Your 2010 paper proposes that Old World monkeys and New World
> > monkeys split about 130 million years ago. That age more than doubles
> what
> > most mammalogists would accept as likely. And your estimate of about 185
> > million years ago for the origin of Primates is roughly triple the
> > generally accepted age.
> >
> > And fossil primates can be identified by mere scraps of different
> > parts of their skeleton, and the morphology of their various teeth have
> > been intensely studied. But I guess you really believe that there were
> > Jurassic and Early Cretaceous primates and that somehow noone has ever
> > found even a scrap of their skeletons in the fossil record between 185
> and
> > 65 million years ago.
> >
> > Extraordinary claims require extraordinary evidence, and Goswami
> > and Upchurch provide many reasons for doubting your extraordinary claims.
> > They didn't call your hypothesis a "fairy tale", but I suspect they
> > probably would have liked to do so. They were just too polite.
> >
> > I would be interested to know if anyone subscribed to Taxacom
> > (besides Michael Heads and John Grehan) find the hypothesis in Heads 2010
> > paper at all convincing.
> >
> >
> > Heads, 2010: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1463-
> > 6409.2009.00411.x
> >
> >
> > Reply by Goswami and Upchurch, 2010: https://www.researchgate.net/
> > publication/229977172_The_dating_game_A_reply_to_Heads_2010
> >
> >
> >
> > ________________________________
> > From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> on behalf of Kenneth
> > Kinman <kinman at hotmail.com>
> > Sent: Tuesday, June 12, 2018 7:10 PM
> > To: Michael Heads
> > Cc: Taxacom
> > Subject: Re: [Taxacom] Oceanic dispersal vs. vicariance
> >
> > Hi Michael,
> >
> > I cannot imagine transoceanic dispersal on an actual floating
> > island with cliffs. However, a huge floating raft composed of many
> > hundreds of trees and soil clinging to the roots of those which were
> upside
> > down seems very possible. So I view some of the anti-vicariance views of
> > Alan de Queiroz as being a bit extreme.
> >
> > On the other hand, I would tend to agree with Goswami and
> Upchurch,
> > 2010, in arguing against Heads, 2010:
> >
> > "Heads (2010) argued for the use of continental break-up dates as
> > calibration points for molecular clocks when the taxon of interest is
> > widely distributed but dispersal across open oceans is considered
> > improbable. Using this method, he estimated that the placental mammal
> > clade Primates originated in the Early Jurassic, requiring a 130 million
> > year ghost lineage before the first euprimate fossils appear in the
> record.
> > We demonstrate that this argument is flawed for several reasons."
> > I cannot imagine ever finding primate fossils in the Early
> Jurassic
> > (or even the Early Cretaceous). I assume John Grehan would probably
> argue
> > for such early primates, but I just can't imagine such a long ghost
> lineage
> > as being likely. I can see rodents living underground (perhaps
> hibernating
> > for an extended period) surviving the Cretaceous-Paleocene extinction
> > event, but not primates.
> > Anyway, as I said before, there seem to be some extreme views on
> > both sides of the debate over vicariance vs. transoceanic dispersal.
> And
> > the truth is very likely in between, and I reject such extremes on both
> > sides of the debate.
> > ------------------Ken
> > P.S. Here is a weblink to the abstract of Goswami and Upchurch, 2010: <
> > https://www.researchgate.net/publication/229977172_The_
> > dating_game_A_reply_to_Heads_2010> https://www.researchgate.net/
> > publication/229977172_The_dating_game_A_reply_to_Heads_2010
> >
> >
> >
> > ________________________________
> > From: Michael Heads <m.j.heads at gmail.com>
> > Sent: Monday, June 11, 2018 5:43 PM
> > To: Kenneth Kinman
> > Cc: Taxacom
> > Subject: Re: [Taxacom] Oceanic dispersal vs. vicariance
> >
> > Ken,
> >
> > There has been no long-standing debate between Alan de Queiroz and
> myself.
> > I helped him out a lot with his book, providing long replies to his many
> > questions about the modern history of the subject in a whole series of
> > emails. I knew he disagreed with my views, but I was happy to help out,
> > even though I was very busy in Mexico at the time. I was surprised when
> the
> > book came out. I was the subject of the chapter 'Over the edge of
> reason'
> > and portrayed as barking mad. (My guess he was looking for a job and
> trying
> > to impress the right people). I wrote one article reviewing the book.
> >
> > I don't have his book with me, but somewhere in it there is a whole page
> > plate of a painting showing a literal floating island - not just a mass
> of
> > vegetation, but a real island, with cliffs, different types of forest
> etc.
> > The island is moving in a straight line across the sea and leaving a wake
> > in its trail. How does that work?!
> >
> > Which cases of trans-oceanic vicariance do you agree with?
> >
> > On Mon, Jun 11, 2018 at 2:25 PM, Kenneth Kinman <kinman at hotmail.com
> > <mailto:kinman at hotmail.com>> wrote:
> > Hi all,
> >
> > I've been reading a variety of papers on the debate (beginning
> > about 2005) between Alan de Queiroz (and others) on the one hand and
> > Michael Heads (and others, incl. John Grehan) on the other. I have come
> to
> > the conclusion that both sides represent polar opposites in the debate
> > between oceanic dispersal and vicariance. The truth is probably
> somewhere
> > in between, meaning that both sides are right about some cases, but wrong
> > in others. Not at all surprising.
> >
> > Perhaps the strongest case for a large number of oceanic
> dispersals
> > is probably from the African mainland to Madagascar. And the case for
> > numerous oceanic dispersals between the African mainland and South
> America
> > (when they were closer together) is more controversial, but there is
> > apparently evidence that some of those dispersals were along island
> chains
> > that no longer exist. Whether such islands existed or not, the debate
> > between the two sides seems to be largely centered on molecular estimates
> > of divergence (about which Grehan seems to repeatedly complain ad
> > nauseum). Therefore, my increasing reluctance to respond to his
> continued
> > "baiting". If he wants evidence, there is lots of evidence in the
> > literature from many authors (many who seem to be somewhat more objective
> > than Alan de Queiroz).
> >
> > The case for oceanic dispersal from Australia (including Tasmania)
> > to New Zealand is admittedly even more controversial. That controversy
> not
> > only involves molecular estimates of divergence, but also whether or not
> > New Zealand was completely submerged at some time in the mid Cenozoic.
> > Therefore, I am playing devil's advocate in suggesting how one or two
> > species of Nothofagus could have rafted from Tasmania to New Zealand in
> the
> > middle of the Cenozoic. Maybe they did and maybe they didn't, but both
> > possibilities should be kept in mind. Given the long-standing debate
> > between Alan de Queiroz and Michael Heads, I find the Nothofagus case the
> > most challenging (even though some earlier Nothofagus dispersals seem
> > likely to have been due to vicariance over land in Gondwana). Nothofagus
> > distribution could be due to a combination of both vicariance and some
> > cases of more recent oceanic dispersal.
> >
> > ------------------Ken
> >
> >
> > _______________________________________________
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> > Nurturing Nuance while Assaulting Ambiguity for 31 Some Years, 1987-2018.
> >
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> Nurturing Nuance while Assaulting Ambiguity for 31 Some Years, 1987-2018.
>
--
Scott Thomson
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