Re: Limbs and niche partitioning

[dbensen <dbensen@gotnet.net>]

>>One niche that opened up was the aquatic environment.  Just a thought
(wildly speculative), but perhaps some of the prerequisites of flight
(feathers and a flapping ability) evolved in response to cursorial
dinosaurs exploiting an aquatic environment.  The higher heat transfer
rate and higher density of water would likely result in stronger
selective response to adaptations affecting insulation or propulsion,
lift and drag, particularly in smaller animals---and without the
hypertrophy of arms or other elements required for aerial flight. Once
those characteristics evolved, exapting them for aerial flight would not
seem to be as big a step as going directly from the ground to the air.  I
wondered about this as I thought about Sinornithosaurus, which apparently
couldn't fly but had integumentary fibers of some sort and a shoulder
girdle capable of a flapping motion.  As I said, wildly speculative.

<<

I believe Greg Paul said something like that in Predatory Dinosaurs, that is,
that early birds (archaeopteryx in particular) may have lived like dippers.
I've never heard the theory attached to Sinornithosaurus, but it sounds
intriguing.  the animal can't be larger than some penguins.  Does it have the
conical teeth of fish-eaters?

Dan