Re: More stuff on early maniraptoriforms

["John V Jackson" <jjackson@interalpha.co.uk>]

--Original Message-- From: Thomas R. Holtz, Jr. <th81@umail.umd.edu>Date: 12
November 1998 14:52


>By the way, what femoral features would you consider diagnostic for a
>maniraptoran?



:)


You know I'd be happy to take your word on anything like that, Tom! (!)

Surely I'm enough of a nuisance when I don't know what I'm talking about -
do you really want me to become an expert?!

On reflection though, fliers' femurs tend to be narrower, and even ex-fliers
tend to have narrow femurs.  Droms' femurs are fairly chunky though.


>>>Perle, Chiappe, and colleagues discuss this subject [[2F]] with regards
to
>>alvarezsaurids in Nature, Science, and elsewhere.
>><
>>
>>That's a start, but I don't think Luis is the best choice for selling the
>>idea.  (Not that Luis, anyway.)
>
>Ideas by merit, not by source.  Repeat until you get the concept.

Yes, sorry . . . when I said that it was 4am.  What I really meant to say
was:

a) I don't know much about Alvarezsaurs, except that I recognised them as 2F
the moment I saw them (tiny toothless head, incredibly long legs, very small
arms, rather stiff tail, very small size).

b) Their 2-flightlessness is pretty universally accepted I think.

c)  It's the other suspects that count, and Chiappe doesn't believe for
example that Protarch/Cauditp. are birds.  Ok it would be nice to hear him
acknowledge eg my theory (but realistically, Greg or George's) but him
saying Alv's are 2F isn't really the point.


>Or, perhaps, that it was the *paper* that got rejected (assuming there was
>even one submitted!!)

I submitted a 'letter' to "Nature".  I *did* I tell you!  They were so
tactful I almost forgave them.  Unfortunately it didn't even get as far as
the peer review stage. ("Reasons of space".)

Oh yes, even accepted 'peers' are subject to editorial indignities.  But I
still wish the odd paper had been printed on 2F in a popular journal, and/or
the theory was mentioned either by opposing specialists or the house
summarisers.  PMLOT  (ie "Probably my last on this") - for a while, anyway.



>
>>Let me say this.  There is a biologist who worked with Haldane to produce
>>much of the bases on which our current understanding of natural evolution
>>rests.  There aren't many who could claim to have been more significant in
>>the field alive today.  Now if Maynard Smith isn't a big fan of
cladistics,
>>what is it that all these other characters know about biology that makes
>>their opinions more valid than his?
>
>Ideas by merit, not by source.  The arguments as to why cladistics is
>currently the favored method of analysis, and a history of the subject, can
>be found in:
>Hull, D.  1988.  Science as a Process.  Univ. Chicago Press.
>
>(And, for the main reasons: explicit delimination of what characters are
>being studied and how they are distributed among the taxa in question;
>repeatablity (precisely what Dinogeorge suggested); falisifiability).

Thanks for the ref.  I think I probably will take that one down.

>
>>>Okay, now we can start discussing these things nice and systematically.
In
>>your opinion (analysis would be preferred, but I'll have to settle for
>>opinion), which of the following groupings most accurate reflects the
>>phylogeny in question:
>>
>><
>>
>>This one:
>>
>>Pinnants (First-ish member - Archae)
>>|
>>| ? --Arctos
>>| ? --Enants
>>| ? --Uncinants
>
>Okay, fair enough.  So, an unresolved trichtomy above _Archaeopteryx_.
>Fine.  Great.

Well, I just don't think we can say any more than that
Arctos/Enants/Uncinants probably weren't mutually nested - as far as the
known members are concerned.  (At least I now know what you mean by
"above".)

>Now, what is the membership of Uncinants again (oviraptorosaurs and
>dromaeosaurids)?

Yes, and anything else with uncinate processes on the ribs ie Neornithines,
(or with uncinant ancestry eg screamers)


>Let's start with the simplest one: what characters unite these three
>advanced taxa above the level of _Archaeopteryx_?

They and they alone all had 'proper' feathers (pace Alan Brush), or
feathered ancestors.

If I have doubts about any of them, it's Tyrannosaurs.  And then troodonts.
But troodonts, with the foot claw, at least show a convincing sign of
ex-arboreality, if not ex-flightedness.  But if we are assured that the
arctos are a sound group, then we're probably ok.  Maybe the Alvarezsaurs
will fit there.  If Therizinosaurs only had sinofur they're outside
'Pinnants', inside them if they had proper feathers; and I'll start worrying
about where when we've seen the colour of their plumage.


>If you want to play the game of exposure, and you don't want to be doing
>pseudoscience (which actually does get a lot more of exposure than science:
>I supect more people know about crop circles than about the Milankovitch
>cycles...), then submit your hypothesis to the test.  If it survives, it
>deserves some attention.  If it doesn't, then it deserves less attention.
>No more and no less can be asked for any scientific hypothesis.


 By 'test' of course you mean the reviewing peers.  I'd be happier if they
were all scientists like JMS - but then again, biological science only
started with the advent of cladistics.

You make a good point when you say "If it doesn't, it deserves less
attention".  This process, of getting exposure proportionately with success
may not be perfect, but it is the way evolution works.  The natural genetic
algorithm apparently comes close to a good solution to the "k-armed bandit"
problem - ie, you have a one-armed-bandit in front of your, but with many
arms.  (For arm, think "scientific theory".)  Each arm doesn't work
everytime, but in the long run each arm has its own an average payout.
Which arms do you pull in order just to find out which ones are the best?
The quickest way is to try them all a bit at random, then try each one
proportionately to its payout so far.

That is how the peer review sytem works at the moment - with the important
exception that only old arms are ever pulled.  That is why it is
particularly damaging to the scientific process that the initial first
couple of introductory trials have always been denied 2F theories, in the
journals that count.


JJ