[Taxacom] Oceanic dispersal vs. vicariance
John Grehan
calabar.john at gmail.com
Tue Jun 12 21:32:30 CDT 2018
Further comments on Ken's latest assertions of belief.
"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."
In reference to Goswami and Upchurch one again runs into belief systems
rather than science. Whether one can believe something or not is not
science. And so Ken also asserts personal belief as some kind of authority
when he states “I cannot imagine ever finding primate fossils in the Early
Jurassic (or even the Early Cretaceous).” Well, I would never criticize Ken
or anyone else for their beliefs, but their beliefs as such have no
scientific merit, any more than Chamberlain who knew Hitler lied, but could
not believe that Hitler would lie to him!
“ I assume John Grehan would probably argue for such early primates”
On the present evidence of correlated distributions I cannot argue
otherwise.
“but I just can't imagine such a long ghost lineage as being likely”
Understood, but what one imagines is possible or not has no scientific
merit. Interestingly, molecular estimates can also create very long ghost
lineages.
“I can see rodents living underground (perhaps hibernating for an extended
period) surviving the Cretaceous-Paleocene extinction event, but not
primates.”
Same.
“Anyway, as I said before, there seem to be some extreme views on both
sides of the debate over vicariance vs. transoceanic dispersal.”
In science there are no ‘extreme’ views.
“And the truth is very likely in between, and I reject such extremes on
both sides of the debate.”
This comes across as a metaphysical assertion. No scientific merit. I guess
Ken is saying that God created the universe to be moderate in its unfolding
and so positioned to exist between any 'extreme' views.
John Grehan
On Tue, Jun 12, 2018 at 8:10 PM, Kenneth Kinman <kinman at hotmail.com> wrote:
> 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
>
> ________________________________
> 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
>
>
> ________________________________
> From: John Grehan <calabar.john at gmail.com<mailto:calabar.john at gmail.com>>
> Sent: Thursday, June 7, 2018 10:08 AM
> To: Kenneth Kinman
> Cc: Michael Heads; Taxacom
> Subject: Re: Oceanic dispersal (rafting) of mammals in particular
>
>
> Hi Ken,
>
>
> Thanks for your latest observations on the subjects. Some reflections
> below.
>
>
>
> “I do not object to vicariance (it explains many distribution
> patterns). I just think panbiogeographers tend to overdo vicariance, and
> you in particular have a tendency to start ranting when vicariance is
> challenged in some cases. So I probably won't be doing any more posts on
> the subject.”
>
>
>
> No problem with that. All counter responses may be viewed that way. That
> is why I have said that what is important is how a particular view is
> connected to the evidence and the nature of that evidence. And why should I
> not 'rant' when vicariance is challenged? Is that not the nature of science
> in general? I suppose one could ignore alternative views and that also is a
> choice scientists often make (at least in evolutionary biology).
>
>
>
> “I will just close by saying that there seems to be a pattern of
> Africa to South America transoceanic dispersal which also includes
> caviomorph rodents, the hoatzin, and lots of different small reptiles
> (amphisbaenians, geckos, skinks, lizards, and blind snakes). So the New
> World monkeys would not be an isolated case.”
>
>
>
> So you keep saying. And I keep asking for your to explicitly state the
> nature of the evidence, which you keep avoiding. I have no problem with
> your presenting your view as we are all entitled to that, but to avoid
> making a reasoned argument as to the nature of the evidence and how that
> indicates your model and falsifies other evidence of vicariance is
> problematic to say the least. It is as if you are trying to protect your
> 'evidence' from external scrutiny (which again is the nature of being
> scientific). If your view is so strongly supported by evidence I would have
> thought you would have no such trouble in presenting that evidence – i.e.
> explicitly stating the nature of the evidence and how it necessarily means
> that vicariance evidence is not real evidence. I get the impression that
> chance dispersal is so obvious to you that you decline to provide the
> supporting evidence and have little patience with your viewpoint being
> challenged.
>
>
>
> As you know, I have analyzed some lizard patterns attributed to
> trans-oceanic dispersal and shown in detail that in these cases there is no
> actual evidence of dispersal and that the patterns conform to a process of
> allopatric differentiation. My arguments and evidence may be contested
> (which is fine by me), but at least I present the nature of evidence for my
> views in considerable detail.
>
>
>
> “There are presumably lots of invertebrates and plants that also show this
> pattern, but I don't have the time to delve into that.”
>
>
>
> No worries, since more assertions of your model would not add anything in
> the absence of evidence.
>
>
>
> “Vicariance does explain lots of Africa-South America relationships, but I
> still think it needs to be challenged in some cases.”
>
>
>
> Challenging vicariance is fine, but it needs evidential argument, not just
> assertions or, as in the literature, misrepresentations of the fossil
> record of calibrated molecular estimates.
>
>
>
> “Anyway, if you want answers to all your questions about such hypotheses,
> you should stop calling the answers fairy tales. I was not surprised when
> Jason said: "None of this is a fairy tale, pseudoscience nor an attack on
> vicariance."
>
>
>
> I can stop calling them fairly tales when they are sequentially connected
> to evidence and that evidence is shown to falsify vicariance. At this point
> all I see are assertions without evidence, or artificially created evidence
> (molecular divergence that is not correctly presented as minimums).
> Actually whether I consider them fairly tales or not is neither here nor
> there. Some critics have characterized panbiogeographic reconstructions in
> a similar manner. It does not matter. In science (as I understand it) the
> issue is always about the presentation and nature of what constitutes
> evidence. This seems to me to be as true for a laboratory experiment as it
> does for historical reconstruction.
>
>
>
> John Grehan
>
>
> On Thu, Jun 7, 2018 at 9:31 AM, Kenneth Kinman <kinman at hotmail.com<mailto:
> kinman at hotmail.com><mailto:kinman at hotmail.com<mailto:kinman at hotmail.com>>>
> wrote:
>
> John,
>
> I do not object to vicariance (it explains many distribution
> patterns). I just think panbiogeographers tend to overdo vicariance, and
> you in particular have a tendency to start ranting when vicariance is
> challenged in some cases. So I probably won't be doing any more posts on
> the subject.
>
> I will just close by saying that there seems to be a pattern of
> Africa to South America transoceanic dispersal which also includes
> caviomorph rodents, the hoatzin, and lots of different small reptiles
> (amphisbaenians, geckos, skinks, lizards, and blind snakes). So the New
> World monkeys would not be an isolated case. There are presumably lots of
> invertebrates and plants that also show this pattern, but I don't have the
> time to delve into that.
>
> Vicariance does explain lots of Africa-South America relationships,
> but I still think it needs to be challenged in some cases. Anyway, if you
> want answers to all your questions about such hypotheses, you should stop
> calling the answers fairy tales. I was not surprised when Jason said:
> "None of this is a fairy tale, pseudoscience nor an attack on vicariance."
>
> ------------------Ken
>
>
> ________________________________
> From: John Grehan <calabar.john at gmail.com<mailto:calabar.john at gmail.com>
> <mailto:calabar.john at gmail.com<mailto:calabar.john at gmail.com>>>
> Sent: Wednesday, June 6, 2018 10:04 PM
> To: Kenneth Kinman
> Cc: Michael Heads; Taxacom
> Subject: Re: [Taxacom] Oceanic dispersal (rafting) of mammals in particular
>
>
> Ken,
>
> What I interpret from your position is that when you think a distribution
> arose by chance dispersal then dispersal explains how they got there, and
> if dispersal occurred more than once and did not succeed we will have no
> evidence of it. And allopatry is due to competitive exclusion and sympatry
> is explained as the lack of competitive exclusion. All of this is fine as
> assertions of your personal belief and there is no falsifying that. What is
> at issue, is how you reach the dispersal conclusion in the first place, and
> for both NW primates and Nothofagus you have not explained that.
>
> Jason makes the argument that if a vicariance event to 'too much' earlier
> than the oldest fossil then it cannot be believed. I don’t know if that is
> your position or if this is your reasoning for Nothofagus and Primates.
> Perhaps you would be so good as to make an explicit statement on that? It
> would go a long way to clearing up the otherwise confusing nature of your
> objections to vicariance. I realize that you do not publish on
> biogeographic method and reasoning, but it might be helpful in general to
> better understand how your views are connected to empirical sources since
> many others may share your particular perspective.
>
> John Grehan
>
>
> On Wed, Jun 6, 2018 at 9:18 PM, Kenneth Kinman <kinman at hotmail.com<mailto:
> kinman at hotmail.com><mailto:kinman at hotmail.com<mailto:kinman at hotmail.com>>>
> wrote:
>
> Well, competition between primate groups in Madagascar and America
> would have only been the deciding factor if there were later oceanic
> dispersals, as in Madagascar after lemurs had become so well-established in
> many different ecological niches. Either way (later dispersals or not),
> the lack of overlap is primarily due to the ocean barriers which are very
> difficult to cross. Without ocean barriers, overlap seems to be primarily
> due to noctural vs. diurnal.
>
>
> It is somewhat similar in the case of Carnivora. In Madagascar you
> only have Family Eupleridae, and any subsequent dispersals of the related
> Family Herpestidae would have been prevented by competitive exclusion.
> Elsewhere, the Herpestidae can overlap geographically with Viverridae,
> because Herpestids are primarily terrestrial and diurnal, while Viverrids
> are primarily arboreal and nocturnal.
>
> -------------Ken
>
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