RE: Armalligator was: Email

G'day,

> Mechanically, it would be more efficient if 
> the legs were vertical rather than sperad 
> out to the sides. Vertical legs support the body
> directly whereas spread legs need energy or some special 
> blocking mechanism to maintain the body in a lifted position.

However, there may be no need to lift if they develop tech, tools etc
that
can be used in a dorso ventrally flattened position. Many crabs are good
at
manipulating stuff with little requirement for lifting up as they do it
this
and while not analogous to the creature in question octopus are
brilliant at
using tools without being in a "lifted position".

> Sounds pretty weird. If the athmosphere is aggressive, where 
> do pure metals come from ? 

They don't need to be pure, just accessible. The metals we use
biochemically
aren't in pure forms.

>Are there any "plants" that photosynthesize them ?

Don't need plants as such, bacterial (sulphur based) chemosynthesis is
more
than enough for the vent fauna etc of Earth and would be more than
likely in
a planet (like Venus) where there is little if any direct sunlight.

> On Earth most animals with a ExS 
> regularly shed the skeleton to grow a new, bigger one. 
> During this time, they are extremely vulnerable. 

I'd be more concerned with reproduction. You don't have to moult once
you're
big enough, or you could just make sure you do it in a "safe place" and
staggered, but on Earth the adults of many exoskeleton using species
moult
more to allow for reproduction rather than growth alone.

> Another option would be to have a skeleton 
> composed only of shapes that can be expanded: 
> flat plates (the triangular design of Oitjuan looks 
> good for this), cones, snail/seashell shapes.

Not a bad idea.

> 
>> Musculature is mostly steel cable,
> 
> Hard to see how this could evolve from primitive organisms

Well steel maybe, but I could live with analogous structures (seeing
some of
the stuff really used on earth is stronger).
 
Cheers

Beth