Re: Microraptor also ate fish

[Tim Williams <tijawi@gmail.com>]

Jason Brougham <jaseb@amnh.org> wrote:


> We have three winged animals weighing about a kilogram.
>
> 1) Perching - adapted raven, Corvus.
>
> 2) Microraptor, with gripping pes.
>
> 3) Pteropus, with no gripping adaptations.
>
> 1 and 3 roost in trees. I don't think you can say, with any logical
> validity,  that there is no way 2 did.



I disagree with the premise of this question.  The feet of _Pteropus_
(fruit bats) have excellent gripping adaptations.  Their toes are very
much like the fingers of other suspensory mammals, and are highly
adapted for suspending the animal from tree branches.*  Thus, the pes
of _Pteropus_ is definitely arboreally adapted.


BTW, I'm not saying that there is "no way" that _Microraptor_ could
roost in trees.  My point is that the pedal morphology of
_Microraptor_ shows no apparent adaptations for roosting or perching.
If you can put together a case that _Microraptor_ indeed has
adaptations for roosting (or perching), then go for it.  This sounds
like a working hypothesis that deserves to be tested.


However, if your argument is that there are no such adaptations in
_Microraptor_, but it was capable of roosting or perching anyway, then
(scientifically speaking) this is where we part company.  There is
nothing to test here.


I don't dispute that _Microraptor_ had a pes capable of gripping.  But
so did the pes of _Deinonychus_.  I remain unconvinced that the
gripping pes of _Microraptor_ allowed it to roost.  But I'd be quite
happy to be refuted on this point, by way of solid biomechanical
evidence.  Intuitively, I really like the notion of an arboreal
_Microraptor_.  However, the anatomical evidence in favor of an
arboreal lifestyle is weak to non-existent.  There is certainly
evidence that _Microraptor_ was scansorial - but this is a long way
from being arboreal.


* Among other sources, the pedal morphology of pteropodid bats  was
discussed (and figured) by Boyer and Bloch (2008) in their chapter on
plesiadapiforms in "Mammalian Evolutionary Morphology: A Tribute to
Frederick S. Szalay.")





Cheers

Tim