Re: Gliders to Fliers? (Was Re: Ruben Strikes Back

["Larry Febo" <larryf@capital.net>]

Dan Bensen wrote:


<<Okay, here's my testament to dinosaur evolution.

    Dinosaurs evolved from quadripedal, cursorial archosaurs (like
Lagosuchus)
in the early Triassic.  These archosaurs
were small predators of the scrub-and-desert that covered most of the world
at
that time, and had several adaptations
for moving around in the sand.  One of these was hopping.
    Although bipedal movement is usually not any more efficient than
quadripedal
(and sometimes more dangerous, as
mbonnan stated).  However, bipedal hopping is much better than quadripedal
running when the animal is on sand.  Many
desert-living rodents and marsupials have evolved bipedalism independently
and
all live in such flat environs.  One
cannot say that bipedalism is a result of aborialism because most arboreal
mammals are quadripedal  Monkeys most
certainly run on four legs and tree kangaroos are bipedal because they
evolved
from bipedal, hopping, ancestors.  So,
these lagosuchians made many specializations toward a hopping gait, and when
the
global climate changed in the
Middle and Late Triassic, it was simpler, evolutionarily, to become bipedal
walkers rather than devolve all their new
traits.  These archosaurs were the dinosaurs, which only descended back onto
four legs when they had to (for reasons
of balance).  Dinosaurs are bipedal by default because they evolved from
bipedal
ancestors, just as mammals are
quadripedal by default because we evolved from weasel or rat-like scurriers
who
needed a limber, sprawling posture.>>

That`s a new view somebody proposed right? That Lagosuchus hopped? Who
proposed that?

I don`t know if you said quadropedal by mistake, but I think it is generally
viewed as being bipedal.

As far as going from a hopping mode to a regular walking gait?? I don`t
know, ...has such a case ever been documented before for any creature?