Re: 11th specimen of Archaeopteryx

[Tim Williams <tijawi@gmail.com>]

Jason Brougham <jaseb@amnh.org> wrote:


> The earliest utility of climbing into trees may have been in roosting, 
> because foraging in trees may require better adaptations to be
> efficient (though Jeholornis somehow did swallow dozens of gymnospem seeds).


Possibly _Jinfengopteryx_ too.


Foraging seeds from cycads or bennettitaleans would require no
perching adaptations, and minimal climbing adaptations.  A proto-bird
scaling a cycad trunk might be analogous to a dromaeosaur grappling
with large prey using all four limbs.


> As I mentioned earlier the newest paper (Prieto-Marquez, Bolortsetseg, and 
> Horner , 2011) places the Archaeopteryx as a sister taxon > to Jeholornis.


I think I'd prefer to see more avialan taxa (like enantiornitheans) in
the analysis before I'm confident in a _Archaeopteryx_-_Jeholornis_
clade.  However, if this does show up in future analyses, then it
might be an opportunity to resurrect the name Sauriurae (or Saururae,
to use the original spelling) for a clade that includes
archaeopterygids and jeholornithids but not crown birds.


> Whether Jeholornis had a reversed hallux or not is apparently a  matter of 
> debate,


AFAIK, metatarsal I is straight and the hallux is fairly high, as in
_Archaeopteryx_.  If so, _Jeholornis_ could not have had a reversed
hallux suitable for grasping.








Cheers

Tim