RE: Microraptor was a competent glider (but nothing to write home about)

[Jason Brougham <jaseb@amnh.org>]

This was first hypothesized for Archaeopteryx by John Videler in Archaeopteryx 
18 (2000) ISSN 0933-288x. A biomechanical analysis by Ming San Ma, et al. in 
Archaeopteryx 20 (2002) found that water running in Archaeopteryx it was 
unlikely.

________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Erik Boehm 
[erikboehm07@yahoo.com]
Sent: Friday, September 20, 2013 5:46 AM
To: dinosaur@usc.edu
Subject: Re: Microraptor was a competent glider (but nothing to write home 
about)

*converted to plain text*
I just had an interesting thought....

I'm sure you are all aware of the basilisk lizard? A relatively small lizard 
with long toes, that can run across the surface of water...
Surely its not the first vertebrate to have evolved the capability to run 
across the surface of water.
I've seen videos of flying fish that have the lower half of their tailfin in 
the water, thrusting even as their body is out of the water supported by their 
"wings"
Many waterbirds today engage in running across water as part of their take-off 
sequence, and as I understand it, a significant portion of the acceleration 
force comes from their feet. So using the wings for "flight" (powered or 
unpowered) higher above the water is not mutually exclusive for using the wings 
for traversing the surface of the water while aided by ground effect.

Feathers on Microraptors feet would increase its surface area, much like the 
long toes of a basilisk lizard, throw in some wings to take some of the load, 
and maybe microraptor could run across the surface of the water... although if 
this was their purpose, webbed feet seem like a more likely adaptation - unless 
maybe the feathered legs were dual purpose (gliding/water running)

Without actually looking at the physical dimensions of microraptor, or doing 
any calculations, I'm not sure if this is plausible...


________________________________
From: Dann Pigdon <dannj@alphalink.com.au>
To: dinosaur@usc.edu
Sent: Friday, September 20, 2013 7:46 AM
Subject: Re: Micro
about)


On Fri, Sep 20th, 2013 at 2:31 PM, Tim Williams <tijawi@gmail.com> wrote:

> Dann Pigdon <dannj@alphalink.com.au> wrote:
> > Gliding across water barriers that you wouldn't want to swim across (due to 
> > the presence of
> crocs,
> > labyrinthodonts, big predatory fish, pliosaurs, etc) would certainly be 
> > useful. It'd enable
> something
> > the size of Microraptor to reach areas that similar sized terrestrial 
> > competitors couldn't
> (without
> > risking being eat

>
> Yes, but how does the glider get out again?  It can glide in... but it
> can't glide out.  Poor _Microraptor_ would be marooned.

They'd have to make sure there were trees on both side of the water barrier, if 
they planned on
returning.

At the very least it might have enabled them to cross potentially dangerous 
rivers with trees lining
both banks. Chimps and bonobos seem to have speciated due to the Congo River 
keeping their
populations separated. For a poor swimmer, a wide or fast-flowing river can be 
a major obstacle.
Even good swimmers might not make it across depending on the ferocity of 
aquatic predators.

--
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia              http://home.alphalink.com.au/~dannj
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