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Re: birds have skulls like baby non-avian dinosaurs



Jason Brougham <jaseb@amnh.org> wrote:

> A new online paper:
>
> http://www.nature.com/nature/journal/v487/n7406/full/nature11146.html
>
> Birds have paedomorphic dinosaur skulls
>
> Bhart-Anjan S. Bhullar, Jesús Marugán-Lobón, Fernando Racimo, Gabe S. Bever, 
> Timothy B. Rowe,
> Mark A. Norell & Arhat Abzhanov
> AffiliationsContributionsCorresponding authors
> Nature 487, 223–226 (12 July 2012) doi:10.1038/nature11146
> Received 15 November 2011 Accepted 16 April 2012 Published online 27 May 2012


Yes, this is a very interesting paper indeed.  But I wonder where
basal avialans such as _Epidexipteryx_, _Jeholornis_ and _Sapeornis_
would turn up in the PCA plot (Fig. 2).


_Epidexipteryx_, _Jeholornis_ and _Sapeornis_ all have skulls that are
superficially similar to oviraptorosaurs: tall and short with a deep
snout.  Would they link the oviraptorosaur cluster to the basal
eumaniraptoran/avialan cluster (including _Archaeopteryx_,
_Anchiornis_, _Confuciusornis_, Enantiornithes)?  Or would they link
the oviraptorosaur cluster to the crown clade (Aves)?  Or would they
simply cluster with the basal eumaniraptoran/avialan cluster?


This is possibly quite important, because according to one
phylogenetic hypothesis (given in the _Xiaotingia_ description) modern
birds evolved from forms that were closer to scansoriopterygids and
jeholornithids than to archaeopterygids and deinonychosaurs.  Would a
PCA analysis of skull morphometrics reflect this?





Cheers

Tim