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

Sat Jan 2 23:38:50 CST 2021

And still, annoyingly, animals move and seeds are dispersed, even over
long distances. Who could imagine that this ever would have an effect
on anything?

As fascinating as these interminable reruns are, I can't help but
notice the parallel between this and Fahrenholz' rule.

Fahrenholz' rule states that ectoparasitic animals that do not have a
free-living stage are bound definitely to their hosts, and thus will
speciate in parallel to these. Stated differently, it predicts that
dispersal from one host to another is of no practical or evolutionary
importance, and that vicariance on a single host lineage is the
exclusive mechanism that dominates louse evolution. This results in
the famous "Parasite phylogeny should mirror host phylogeny", which
inevitably lead to the idea that *any* louse species found on a novel
host species must represent a new species; if on a new host family or
host order, it may represent a new louse genus. Morphology was
speedily disregarded by the maxim "It is methodologically more correct
to say that we don't know the morphological differences than to state
that there are none" (Eichler, 1942 I think). Multitudes of species
were then described based on host associations (or with the regular
phrase "Species X is well separated from other species by characters
of the head", with no details or detailed illustrations). This
artificial host specificity was subsequently taken as evidence for
Fahrenholz' rule, in an excellent example of circular reasoning.

In recent decades, both morphological revisions and molecular work has
been very unkind to Fahrenholz. Both lines of evidence have
independently shown that host specificity varies greatly and some
species of lice occur on great numbers of hosts with few or no
morphological and genetic differences between populations on different
host species. The same species of lice is known to be well established
on host species belonging to different orders in many cases (e.g.
buzzard, falcons, and pigeons). In other cases, of course, there are
high degrees of co-speciation and host specificity; it all depends on
the groups examined. In general, the more louse species there are in a
genus, the more likely it is that there will be some species that
break Fahrenholz' rule. We recently published an example of a species
that is known (genetically, it is not described yet) from over a dozen
different host families ranging from Australia and the Philippines
through South China all the way to Malawi. Specimens from across this
range are genetically more or less identical, and there are no real
morphological differences other than what may be expected within a
species. From morphological samples, we have found about 50 more host
species, which include more or less the whole Old World tropics, and
about 20 different host families.

Similarly, groups of genera that are morphologically and genetically
very similar occur on widely distantly related hosts. We recently
realised that lice on pigeons, penguins, sandpipers, and grebes form a
monophyletic group genetically, and share at least two morphological
characters that are not found in any other lice. Yet these bird groups
are not very closely related at all. Similarly, the
Degeeriella-complex occurs on a range of distantly related bird
groups, with no obvious patterns (e.g. some but not all kingfishers,
grouse and pheasants but not other galliforms, some New Guinean
passerines and pittas, but barely any other passerines, etc.). At the
time of writing, there is not a single published example that has been
studied in any detail during the last 30 years in which Fahrenholz'
rule applies without exception.

Thus, even millimetre-long lice, that live their whole life on the
host, and have no free-living stage and no intermediary hosts, and
cannot move even a centrimetre on a non-feather surface, can somehow
move between hosts, including over vast distances and between
distantly related hosts and establish viable populations there. There
are many different mechanisms known for this (water walking, phoresy
on flies, etc.), and many of these have been dismissed by adherents of
Fahrenholz' as having no or little impact. Yet obviously they have.
Comparisons with animals that can actually move longer than a few
millimeters on their own volition are perhaps obvious to all.

These days, Fahrenholz' rule is all but abandoned, except in the sense
of a null hypothesis that can be tested. The great adherents to this
rule (Eichler, Zlotorzycka, etc.) are all gone. Of all the louse
researchers in the world, there seems to be only one person who gives
this idea any credence any longer; he published a half-hearted defence
of this rule last year, reiterating Eichler's comment from 1942
paraphrased above. The pretty pattern so dogmatically adhered to by
would-be-theoreticians is ruined completely by the fact that animals
move.

---

Now I am off to work on my 2021 bird list. Interestingly, on my
wish-list for the day is the Japanese Grosbeak, which normally breeds
in the north of China, Japan, and Korea, but which winters here in
Guangzhou. In recent years, they have attempted to breed here as well,
in a sort of microcosm of dispersal. At least one pair got fledged
chicks the year before last, so it remains to be seen if they will be
able to establish a viable population. Yet to my knowledge -- and this
is perhaps illuminating -- Japan did not split from South China
tectonically at any point during the last three years since I arrived
here. Of course, I don't read Chinese so I may have overlooked it, but
I would imagine that that sort of thing would be mentioned in the
international press as well.

Cheers!

On Sun, Jan 3, 2021 at 6:03 AM John Grehan via Taxacom
<taxacom at mailman.nhm.ku.edu> wrote:
>
> Hi Ken,
>
> Understand that you feel that way since it seems that you and Jason are
> frustrated when your claims or interpretations are contested. But
> regardless, the bottom line remains the same:
>
> 1) fossil calibrated molecular divergence estimates are minimums only
> (claims for anything else is indeed transmogrification)
> 2) Priors are just guesses
> 3) molecular clocks are not set in stone as the only arbiter of
> phylogenetic age
> 4) Older tectonic ages are not falsified by fossil calibrated ages (since
> the latter are just minimums)
> 5) tectonic correlations are empirically observable
> 6) No one (to my knowledge) has provided an empirically grounded
> falsification of any proposed tectonic correlation (i.e. demonstrated that
> taxa are younger than the correlated tectonics)
> 7) Panbiogeographic studies have generated novel geological predictions
> that have subsequently been corroborated by geologists - its one case where
> evolutionary theory is not simply a matter of belief, but an actual means
> of predicting new knowledge that was later found to be true (I notice those
> who dismiss panb biogeography step around this one :)
>
> Cheers, John Grehan
>
> On Sat, Jan 2, 2021 at 4:52 PM Kenneth Kinman via Taxacom <
> taxacom at mailman.nhm.ku.edu> wrote:
>
> > Thank you Jason,
> >         You present an excellent critique of "CP" panbiogeographers
> > arguments.   Almost always the same old rigmarole of cherry-picking,
> > quoting out of context, sophistry, circular argumentation, and other
> > methods of muddying the waters.  And it is often cloaked within a barrage
> > of other verbiage, so I agree that it is important to warn newcomers.
> >
> > ________________________________
> > From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> on behalf of JF Mate
> > via Taxacom <taxacom at mailman.nhm.ku.edu>
> > Sent: Saturday, January 2, 2021 12:35 AM
> > To: Taxacom <taxacom at mailman.nhm.ku.edu>
> > Subject: Re: [Taxacom] Molecular evidence (in 2017) supports my 2014
> > theory about rafting killifish
> >
> > I think that Rob was on the right track but not precise enough. It is not
> > that panbiogeography is akin to creationism, it is that the defence John
> > and Michael are mounting is reminiscent of creationists. I may be wrong in
> > your intention but the arguments I hear are cherry-picking, sophistry,
> > circular argumentation and in general muddying the waters so as to create a
> > gap for a "Panbiogeography of the gaps". This, however, is a mistake and
> > has left you holding an untenable arcane view of biogeography whilst
> > ignoring the last 60 years of advances in phylogenetics. The debate
> > strategy seems to me to be a kafkaesque attempt to neutralize any
> > possibility of criticizing Croizat or panbiogeography by labelling as
> > suspect all other contenders, molecular phylogenetics (you call it
> > phenetics), fossil calibration (using minimum age as a the fine edge of the
> > wedge to push arguments such as confusing point calibration with log
> > distributions), molecular clocks (your definition is "strict clock" from
> > the 1960´s but you don´t care), and generally weaponizing the widely
> > acknowledged limitations of all of these and more fields.
> >
> > John, you asked me to argue why I said that your position on Croizatian
> > Panbiogeography (CP) was untenable. Succinctly, because of two main
> > reasons. Firstly because Croizat quite simply rejected cladistics, and if
> > you accept cladistics you are a vicariance cladist by definition and
> > arguing otherwise is rejecting reality Secondly, because CP rejects
> > dispersal (“Interestingly it is dispersalism that invokes miracles and
> > mysteries.”) in spite of evidence that demonstrates that, however
> > infrequently, it happens. Trying to relabel cases of dispersal as "range
> > expansion" is sophistry aimed at making panbiogeography unfalsifiable.
> >
> > This pattern of muddying the waters is particularly noticeable when you
> > selectively quote, for example with Donoghue and De Baets. From the same
> > 2016 publication: "Biogeographic and fossil calibrations are complementary,
> > not competing, approaches to constraining molecular clock analyses,
> > providing alternative constraints on the age of clades that are vital to
> > avoiding circularity in investigating the role of biogeographic mechanisms
> > in shaping modern biodiversity." (2016). I don´t think any biogeographer
> > would disagree with this statement, but it is anathema with CP because, as
> > John has said: “If molecular clock models incorporating a tectonic
> > correlation result in unacceptable results, that does not invalidate the
> > tectonic correlation. But it does raise questions about the molecular
> > model. Nothing ridiculous about it at all.”  The unfalsifiability of CP in
> > all its glory. If something disagrees with CP, CP is not at fault because
> > it is perfect. Other examples of cherry-picking involve the numerous out of
> > context quotes of researchers acknowledging the caveats of phylogenetics
> > and calibration as evidence of the inferiority and mendaciousness of non CP
> > researchers (“magic”, “dark art”, “lies”, etc).
> >
> > This pattern is so extensive it is tiring pointing out the examples:
> >
> > “...keep in mind that some molecular systematists are recognizing that
> > fossil calibration only provides minimum ages and are looking to tectonic
> > correlates instead - which is another way of saying that they have adopted
> > this panbiogeographic method.” ML or Bayesian models do not assume point
> > dates but a probability distribution into the past. Please stop confusing
> > the terms.
> >
> >
> > “The idea that there has to be a constant molecular clock throughout the
> > phylogenetic history of a group is not an empirical finding. It is a model
> > of evolution that may not be true. … Like priors, molecular clocks are also
> > theoretical models (and there are different models) and open to question or
> > refutation. I would like to see you, Ken, show how a constant molecular
> > clock” A molecular clock model does not assume monotonic (constant) rates
> > within genes or within lineages nor are clocks assumed a priori.  This is a
> > straw man argument. Nobody assumes the strict clock a priori except in very
> > specific cases like viruses and even then after testing. I can´t believe
> > that this is a mistake when you guys selectively quote dos Reis et al 2016:
> > “Thus, while the clade ages generated in Bayesian studies are extremely
> > precise and have excellent statistical support, because of the problem of
> > the priors they can be ‘grossly inaccurate’ (dos Reis et al., 2016) and
> > could be tens or even hundreds of millions of years too young.” Cherry
> > picked quote: “Errors in the time prior and in the rate prior can lead to
> > very precise but grossly inaccurate time estimates. Great care must always
> > be taken in the construction of fossil calibrations and in the
> > specification of priors on times and on rates in a dating analysis.” Not
> > quite the same meaning, in particular with the added sentence ending “tens
> > or hundreds of millions of years…”. That is a misquote if I ever saw one.
> >
> > “We see this in the morphological aspect of molecular genetics where
> > different groups separated or dislocated by a tectonic feature show
> > different levels of morphological divergence (for example with the NZ
> > Alpine fault dislocation where correlated distributions may be conspecific
> > or species level differences even after more than 20 million years. So the
> > panbiogeographic implication of tectonic correlation is that this provides
> > an approximation of age for the correlated groups.”
> > You are assuming as axiomatic that the taxa on either side of the fault
> > have been unable to cross since the tectonic event.
> >
> > “As Hauenschild et al. (2018) observed, clade ages that are too young may
> > be calculated ‘based on too narrowly set priors, and vicariance thereby may
> > be erroneously ruled out’.”
> >
> > Again, cherry-picked, out of context quote. It is followed by: “If the
> > importance of vicariance in the course of the Gondwanan breakup is to be
> > evaluated via the pragmatic criterion of mismatch between age estimates and
> > geological history, the priors defining the molecular dating analyses have
> > to be solid. As those are predominantly influenced by fossil attribution
> > (Magallón, 2014; Pirie, Litsios, Bellstedt, Salamin, & Kissling, 2015; Shen
> > et al., 2016), taxonomy and phylogeny of the study group are of crucial
> > importance. Consequently, taxonomically resolved groups with a rich fossil
> > record should constitute ideal model groups, because they are more likely
> > to uncover accurate age estimates (e.g., Favre et al., 2016; Muellner‐Riehl
> > et al., 2016).”
> > And what did the authors find?
> > “Results: Our biogeographic analyses illustrate that the ziziphoid lineage
> > was influenced by both long‐distance dispersal and Gondwanan breakup
> > vicariance events. Yet, these vicariance events cannot explain all
> > divergence events at the backbone of this lineage.” Shocker, they find both
> > mechanisms at play. I can´t wait to see how you ignore this part of the
> > paper whilst using the bits that you agree with (usually the necessary
> > acknowledgement of study limitations).
> >
> > This is a pattern. I have kept correspondence for the last 10 years on
> > these exchanges and it is always the same rigmarole. But I still bite
> > because it is important to warn newcomers.
> >
> > Happy New Year everyone.
> >
> > Jason
> >
> > On Sat, 2 Jan 2021 at 09:03, John Grehan via Taxacom <
> > taxacom at mailman.nhm.ku.edu> wrote:
> >
> > > p.s. keep in mind that some molecular systematists are recognizing that
> > > fossil calibration only provides minimum ages and are looking to tectonic
> > > correlates instead - which is another way of saying that they have
> > adopted
> > > this panbiogeographic method.
> > >
> > > John Grehan
> > >
> > > >
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