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Re: Microraptor Had Iridescent Plumage



Ben Creisler <bcreisler@gmail.com> wrote:

> Microraptor likely
> glided and landed differently from any modern birds as suggested by
> studies and illustrations.


No arguments there!


> If it often landed belly-forward on
> vertical tree-trunks more like a flying squirrel as the artwork
> suggests rather than belly-downward on branches or the ground as
> modern birds do, an alula may not have worked. Clearly a better
> understanding of the function of the metatarsal feathers is needed.


Flying squirrels are highly adapted for arboreality.  _Microraptor_
was not.  The skeletal anatomy of _Microraptor_ weighs against an
ecology that involved gliding between (or within) trees.  The current
evidence points to fairly advanced parachuting/gliding abilities,
without specialized arboreal abilities... which seems odd at first
glance.  But it fits an ecology in which these paravians occasionally
ventured up trees (for whatever reason), and used their 'wings' to
help them return to the ground.  IMHO, this is the most parsimonious
explanation for reconciling the skeletal and integumental anatomies.


> The artwork also shows Microraptors perched on branches. I'm wondering
> if a Microraptor could actually land on a branch like a modern bird.


The medially directed first toe was not suitable for grasping branches
- even sturdy ones.  According to the RPR hypothesis (Fowler et al.,
2011), the grasping foot of dromaeosaurids was achieved by using the
first toe to oppose the fourth toe.  This is very different from the
anisodactyl condition of perching birds, in which the reversed first
toe directly opposes the third toe - a configuration that is ideal for
grasping branches (true perching).  There is no evidence that
_Microraptor_ was capable of perching, even in the loosest sense.






Cheers

Tim