RE: Complete juvenile theropod unveiled in Germany

[Jaime Headden <qi_leong@hotmail.com>]

  As I am sure Mickey will remember, and I've said before, the type of 
*Juravenator starki* is represented by a juvenile. The large head? That's a 
juvenile "thing," and it's been demonstrated in enough ontogenetic 
presentations that I shouldn't need to qualify it at this moment. As also 
mentioned, the close similarity of juveniles in other groups of reptiles tend 
to be very close together: later ontogeny is where development of unique 
features begin, but homogeneity is the rule at the hatchling level. It gets to 
the point that a juvenile, especially a hatchling, bears absolutely no real 
autapomorphic attributes unless that taxon is _so unique_ as to differ from 
entire swaths of close kin. Yes, a lot of what I am saying is anecdotal, but I 
am fairly certain that it is, at this time, improbable to even attempt to infer 
that either specimen should be the same taxon, much less _different_ taxa. It 
does the science of systematics no favors.

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: Thu, 13 Oct 2011 07:02:52 -0700
> From: mickey_mortimer111@msn.com
> To: dinosaur@usc.edu
> Subject: RE: Complete juvenile theropod unveiled in Germany
>
>
> Although of course my opinion could change based on the published 
> description, I stand by my earlier identification of the new theropod as 
> something like Juravenator, if not a member of the same genus.  It has all of 
> the diagnostic characters of Juravenator listed by Chiappe and Gohlich (2010) 
> which can be evaluated- large skull, few maxillary teeth, subequally long 
> antorbital fenestra and orbit, identical humeroscapular, metatarsofemoral and 
> scapulofemoral ratios, scapula narrowest at neck, etc..  It doesn't have 
> Juravenator's supposed maxillary notch, but I've always argued that was 
> taphonomic.  All of the bones look pretty much identical- the scapula, ilium, 
> manus proportions, obtuse lacrimal, very short and high bases on the unguals, 
> maybe even the odd vertically projected and curved caudal prezygapophyses 
> (though these are hard to make out in the new specimen).  Of course at least 
> some of these are probably due to young age.  Maybe compsognathids as 
> currently recognized are united by ontogenetic features and at least some 
> taxa like Juravenator and Scipionyx are baby carnosaurs or megalosaurs 
> instead of coelurosaurs.  But I'd be very surprised if this specimen and 
> Juravenator aren't the same kind of theropod, whatever they are.
>
> Mickey Mortimer
>
> ----------------------------------------
> > Date: Thu, 13 Oct 2011 08:03:05 +0200
> > From: saichania@gmail.com
> > To: DINOSAUR@usc.edu
> > CC: dinosaur@usc.edu
> > Subject: Re: Complete juvenile theropod unveiled in Germany
> >
> > El 13/10/2011 4:18, Jura escribió:
> > > Do we have an idea of where this little guy fits in the theropod family 
> > > tree?
> >
> > According to Oliver W.M. Rauhut and Christian Foth, it's a basal
> > tetanuran, a basal megalosauroid.
>