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RE: 11th specimen of Archaeopteryx‏



  But I was generalizing. I was doing so _because_ I was trying to discuss, not 
end discussion; it doesn't help I don't have all references, but that is why I 
am not actually just saying something is _so_, unlike Fowler.

  The data is not simply assessing claw size/curvature variation, it is about 
the specific of geometry and function, and how this interacts with behavior, 
and how the latter cannot even be inferred for fossil taxa. It tells us nothing 
about what we are meant to do with determining functional use in the manual 
unguals of "raptorial" theropods (part of the point of Manning et al., 
available here: http://onlinelibrary.wiley.com/doi/10.1002/ar.20986/full ). My 
comments were generalizing because there are people making broad sweeping 
statements without noting the total evidence involved. Which, in our 
discussions in particular on my blog, to which you are referring, focus on my 
comments about developing a taxonomic scheme after lumping specimen complexes 
into a taxon. It is like telling me that a straight, broad tooth crown with no 
serrations and fluting should belong to a spinosaurid theropod because ... 
because! I mean, the functional relationships of the tooth are the same, re!
gardless of whether the morphology can occur in crocs, large fish, 
mosasauroids, etc. Microstructure analysis, isotope analysis, and (dare I say, 
a hint of self-skepticism) prevents these teeth from simply being lumped into a 
given taxonomic container, be it "family" or "genus" or "whatever." The same is 
true of non-tooth specimens, or lumping complexes of toe bones into functional 
arrays without assessing finer particulars (such as their microstructure).

  My argument has been, specifically, that the large ungual of the second pedal 
digit is so very different from the other unguals that one cannot simply make a 
bold statement in regards to the total behavior of the foot. Sheesh, John 
Ostrom made this observation back in the 70s and 80s!

  And I am not even getting into cross-sectional geometry, nor the potentially 
highly distinct issue of reconstructing keratin sheaths over bony unguals, and 
the relative problems involved when one is lacking.

Cheers,

  Jaime A. Headden
  The Bite Stuff (site v2)
  http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)


----------------------------------------
> Date: Tue, 8 Nov 2011 18:12:53 +0000
> From: df9465@yahoo.co.uk
> To: dinosaur@usc.edu
> Subject: Re: 11th specimen of Archaeopteryx‏
>
>
>
> I have followed this thread with interest, as I have papers on the subject 
> published and pending (waiting on seeing the reviews for the MS based on my 
> Bristol 2009 talk; so I won't elaborate here due to embargo etc).
>
> The generalized statements weren't even right generally. They aren't based on 
> any published study, or even any casual observance of bird feet/claws, even a 
> google image search can show that you are wrong.
>
> Discussion on claw size distributions in birds is published in Fowler et al. 
> (2009; and references therein). Climbing birds (woodpeckers e.g.) have a 
> zygodactyl foot, with 2 forward and 2 backward facing toes. One toe of each 
> pair is typically large, the other small, with the forward facing toes larger 
> than the backward pair. The foot has this symmetry related to how the 
> woodpeckers move up and down trunks, sometimes upside down (although usually 
> the right way up, hence the anterior facing toes are larger). Perching feet 
> and climbing feet are very different. perching feet (assuming they are 
> adapted specifically for perching) are anisodactyl (3:1) not zygodactyl 
> (2:2). Claw size distribution varies strongly depending on what feet are 
> doing. D-I is usually largest in non-cursors. Non-carnivorous birds usually 
> have a D-III that is largest of the forward facing toes, followed by D-II, 
> then D-IV. Carnivorous birds have a D-II that is as large, slightly
> larger, or much larger than D-III; D-IV is smallest. Active predators usually 
> have claws that are more curved than non-predaceous carnivores (although see 
> fowler et al on owls). There are all sorts of exceptions etc, depending on 
> specific behaviours. how this all ties into paravian evolution is the subject 
> of our upcoming paper (PLoS One; reviews completed; literally waiting on 
> response any day now).
>
> My point: there's often a lot of discussion and "facts" thrown about on this 
> list. You always seem very quick to provide critiques of others work here and 
> on your blog, without writing any papers of your own, or (as noted here) 
> sometimes not having read the relevant literature on what you are discussing. 
> This list isn't a peer-reviewed journal, I understand that, but it is a very 
> public outlet for discussion of research, so when I see a string of 
> "generalized statements" that are almost all very wrong,  I think there is a 
> responsibility to point this out.
>
>
>
> ----------------------------------
> Denver Fowler
> df9465@yahoo.co.uk
> http://www.denverfowler.com
> -----------------------------------
>
>
> ________________________________
> From: Jaime Headden <qi_leong@hotmail.com>
> To: Denver Fowler <df9465@yahoo.co.uk>; Dinosaur Mailing List 
> <dinosaur@usc.edu>
> Sent: Tuesday, 8 November 2011, 10:17
> Subject: RE: 11th specimen of Archaeopteryx‏
>
>
>   I appreciate the absolutely informative and instructive email Denver Fowler 
> replied with to my generalized statments regarding claw morphology and extant 
> versus nonextant paravian theropods. The citations provided within by Fowler 
> in refuting my statement, rather than labelling statements "you are wrong," 
> while at the same time requiring me to provide statements to back up mine is 
> the epitome of providing accurate and complete disclosure when making such 
> generalized statements. I thank Fowler for his ultimately instructive reply 
> to my email.
>
> Cheers,
>
>   Jaime A. Headden
>   The Bite Stuff (site v2)
> http://qilong.wordpress.com/
>
> "Innocent, unbiased observation is a myth." --- P.B. Medawa
> ave and met a stranger with a
> different language and a new way of looking at things, the human race
> has had a dream: to kill him, so we don't have to learn his language or
> his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
> Backs)
>
>
> ----------------------------------------
> > Date: Mon, 7 Nov 2011 22:02:41 +0000
> > From: df9465@yahoo.co.uk
> > To: dinosaur@usc.edu
> > Subject: Re: 11th specimen of Archaeopteryx‏
> >
> > _______________________________
> > From: Jaime Headden <qi_leong@hotmail.com>
> >
> > > This is not entirely consistent with arboreality, although that is 
> > > possible, because climbing birds do not use just one ungual for 
> > > climbing...
> >
> > Yes, I agree.. oh hang on (!):
> >
> >
> > >..., they use all forward-projecting unguals,
> >
> > Do they? Which climbing birds? What do climbing bird feet look like? Are 
> > they different from perching bird feet? do you have a citation that 
> > explains this? (hint, you are wrong).
> >
> >
> > > In birds, while the unguals are graded largest to smallest moving from 
> > > toe two through toe four, then toe one,
> >
> > Are they? which birds? do you have a citation that shows this? (hint, you 
> > are wrong)
> >
> >
> > >the unguals even in raptorial birds are relatively similar in size
> >
> >
> > Are they? which raptors? do you have a citation which shows this? (hint: 
> > you are wrong)
> >
> >
> > >(cassowaries are freaks with straight pdII-3u's, ignore them)
> >
> > Correct. The only thing you got right so far.
> >
> >
> > >; in dromaeosaurids, the pdII-3u is often twice the length of any other 
> > >ungual, a suspiciously bizarre distinction that enforces a functional 
> > >difference, especially in the strong curvature relative to the other 
> > >unguals. And recall, despite the huge!
> > pdII-3u, the other pedal unguals are _terrestrially_ adapted, even in 
> > *Archaeopteryx lithographica*. Moreover, it is questionable how one arrives 
> > at a conclusion that the highly recurved, huge forward ungual is indicative 
> > of "perching" or arboreality to begin with, merely that climbing is _not_ 
> > excluded.
> >
> >
> >
> > Paper is nearly here (hopefully b4 xmas). T
> e to go back and read some papers on claw morphology. You need to.
> >
> >
> > D.
> >
> > PS. I wrote Fowler et al. 2009. It has lots of claw data in it. Your email 
> > didn't.
> >
> >
> > ----------------------------------
> > Denver Fowler
> > df9465@yahoo.co.uk
> > http://www.denverfowler.com
> > -----------------------------------