Re: Herbivory widespread in Coelurosauria

[Tim Williams <tijawi@gmail.com>]

GUY LEAHY <xrciseguy@q.com> wrote:

> A free .pdf is available at the link:
>
> http://www.pnas.org/content/early/2010/12/10/1011924108.abstract



Ironic, for a group called the "Maniraptora"!  Among maniraptorans,
deinonychosaurs such as _Velociraptor_ were the odd-men-out in having
a hypercarnivorous diet.


Given the dietary opportunism inferred for coelurosaurs, especially
the omnivorous habits inferred for basal paravians, this got me
thinking about the origin of flight in theropods.  What if the
evolution of wings was tied in with this opportunistic/omnivorous
lifestyle?  Small maniraptorans searched on the ground and in small
trees for food - small prey (like insects and small vertebrates) and
energy-rich fructifications.  Because these maniraptorans were so
inept at climbing and perching, their arboreal forays were brief, and
those elaborate feathers on the limbs and tail were developed for one
reason: to help get them *out* of trees and back to the ground.  In
other words, wings evolved as an arboreal exit strategy - to return
opportunistically arboreal maniraptorans to the ground, where they
were most at home.  After climbing a trunk and grabbing some tasty
cones off a branch, the maniraptoran says "I'm outta here", and
spreads its wings to descend.


This fits with a dual-mode lifestyle for basal birds and related
winged paravians: scansoriopterygids, _Jinfengopteryx_, _Anchiornis_,
microraptorines, probably basal oviraptorosaurs, such as
_Protarchaeopteryx_/_Incisivosaurus_ - though not caudipterygids, in
which the arms were presumably too short for climbing.  This is an
idea I've been mulling over for a while now, and I might turn it into
a paper if/when I have the time.




Cheers

Tim