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RE: Problems with paedomorphic bird skull paper



I look forward to your opinion once you look at it in detail.  It's true I have 
extremely little knowledge of GM, and I considered the possibility that I was 
making a basic mistake.  Yet even if the splines only indicate differences 
compared to the consensus as opposed to the original configuration, juvenile 
Alligator and Confuciusornis can't be so similar for the reasons I noted at the 
end.  Confuciusornis' large posteriorly placed nares would differ from the 
consensus in a different way than Alligator's small anteriorly placed ones, so 
those points on the splines would not overlap.  Ditto for the quadratojugal 
that reaches far anterodorsally to contact the postorbital in Alligator, while 
Confuciusornis' is small and posteriorly confined.  These would differ from the 
consensus in different ways, yet in Bhullar et al.'s figure they almost 
perfectly overlap. How is this possible?

Mickey Mortimer

----------------------------------------
> Date: Mon, 23 Jul 2012 10:17:19 +0100
> From: paleovouga@gmail.com
> To: mickey_mortimer111@msn.com
> CC: dinosaur@usc.edu
> Subject: Re: Problems with paedomorphic bird skull paper
>
> Hi Mickey,
>
> I've just take a very brief look on your post "Does Confuciusornis
> really have a skull configuration like juvenile Alligator? ".
>
> Taking by granted that your Geometric Morphometrics (GM) knowledge is
> average I just want to remember one thing on this group of morphometric
> techniques:
>
> 1 -- the "wireframes" (Splines) indicate locations of deformation of an
> individual compared to the consensus and not the original landmark
> configuration.
>
> Saying this I will read more carefully your post.
>
> Best
>
> Luis Azevedo Rodrigues
>
>
>
> --
> Luis Azevedo Rodrigues
> Paleontologist (PhD)/Science communicator/Teacher
> Publico Newspaper invited blog/Science Blogs Brazil
> Ciencia Ao Natural - cienciaaonatural.net
> twitter.com/CienAoNatural
> independent.academia.edu/LuisARodrigues
>
>
>
>
> On 23-07-2012 09:57, Mickey Mortimer wrote:
> > You have all probably seen Bhullar et al.'s new paper saying birds have 
> > skulls that resemble those of juvenile theropods and crocodilians. The most 
> > popular figure has been figure 4, "showing the nearly identical skull 
> > configuration of [juvenile Alligator and adult Confuciusornis] and 
> > indicating
> > paedomorphic cranial morphology in Confuciusornis." When I first saw that, 
> > I thought it was odd to use Confuciusornis, since it had such an odd skull 
> > for a basal bird. I commented on that on Jaime Headden's blog, and Bhullar 
> > replied, saying Confuciusornis' skull wasn't very different from other 
> > early birds like the Montsec enantiornithine juvenile. Setting out to test 
> > this, I discovered Bhullar et al.'s wireframes don't match the skulls they 
> > supposedly belong to at all, and that a real wireframe comparison between 
> > Confuciusornis and juvenile Alligator would show a lot of differences. 
> > Check out the details at my blog- 
> > http://theropoddatabase.blogspot.com/2012/07/does-confuciusornis-really-have-skull.html
> >  .
> >
> > Mickey Mortimer
> >
> >
>
> --
> Luis Azevedo Rodrigues
> Paleontologist (PhD)/Science communicator/Teacher
> Publico Newspaper invited blog/Science Blogs Brazil
> Ciencia Ao Natural - cienciaaonatural.net
> twitter.com/CienAoNatural
> independent.academia.edu/LuisARodrigues
>