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RE: Bipedal apatosaurs and stegosaurs? (fwd)



[This message came to me from LN Jeff, but I'm inferring from the tag
 line that it was a message Peter sent to him.  I've thus modified the
 "From:" lines to show it's origin from Peter.  My apologies if I've
 erred.  While I'm here, I should note that I'm about to go out of
 town until next Wednesday.  Chris Nedin has foolishly agreed to put
 mail through in my absence.  Let's all hope he fairs better than Ron!
 -- MR]


Jeffrey Martz wrote:

> 1.  Nobody has any idea how dense the forest was (or how large the trees 
> were) in ANY sauropod inhabited environment.  
 
Generally, the trees that were dominent in environments dominated by 
sauropods were Conifers.  The average height of living conifers is anywhere 
from 70'-200'.  I believe there are trees from the late Triassic of the 
American Southwest whose heights have been estimated at 150'.  I am assuming 
that conifer height has remained fairly consistant for the past 300 million 
years.  My point is that any forest that was sparce enough to let a 
Diplodocoid walk through on all fours would hardly be called a forest because 
the trees would be so few and far between.

> 2.  Sauropods had long but very FLEXIBLE necks and tails.  Why would they 
> have had a problem manuvering around trees?  I think that saying they 
> couldn't have moved around in a forest on all fours is like saying an 
> anaconda couldn't possibly inhabit a jungle because it is longer than the 
> distance between trees.  The only really limiting factor for a sauropod 
> would be the WIDTH of its body, and bipedal walking certainly wouldn't 
> fix that.

They indeed had long flexable tails, BUT their necks that stuck generally 
straight out in front of them, NOT up in the air like in other sauropods, 
were not very flexable; certainly not flexable enough to walk through the 
extremely sparce forest I diagrammed in my last post.  Compairing sauropods 
to anacondas is insane.  Barosaurus and anacondas are built totally 
different.  Whereas the entire body of the anaconda is flexable, a great 
portion of the body of a Barosaurus is relatively inflexable.  Also, if you 
really want to make that comparason, it would be more like an anaconda trying 
to manoeuver through a group of sticks about three inches apart and try to 
weave about looking for the better folliage that just happened to be in front 
of its face.

> 3.  The front legs of sauropods are pretty massively built, with big 
> scapulae.  It would be kind of an overkill in design if all they were 
> doing with thier legs was steadying themselves against trees.

Did you miss the whole genesis of this thread?  It was started because GSP 
suggested that Apatosaurus, Dicraeosaurids and Stegosaurids might have 
habitually walked bipedally because they had poor motor control of their 
forelimbs and had exceptionally WEAK forelimbs compared to other sauropods.

Peter Buchholz
gpb6845@msu.oscs.montana.edu

Los Angeles loves love.