Re: Where did my posting go?????? and Info

["Matthew Bonnan" <mbonnan@hotmail.com>]

Jaime:

You said:
Not to say you were lying, Matt, which I certainly
hope I didn't imply! But to say that the statement was
not correct given my perusal of the paper in question.

D'oh.  No offense taken.  Actually, I should be the one apologizing to you.  
That was one of those late night e-mails, and I was ticked about my message 
not having gone out, so I sincerely apologize coming off like I did.  I read 
my posting this morning and went, "oh, boy, I really sound lame."  My bad. 
=)  I don't want anyone to be "afraid" (ha, right, of me????) to ask about 
or challenge the stuff I put on the dino list.  I am only a graduate 
student, and very fallible.

You are right, of course, the darn thing does have a calcaneal tuber.  I 
suppose my point was that since it is very ornithodiran, and since the tuber 
is relatively small, I have my doubts that Marasuchus is a leaper based on 
foot and limb aspects.  The long tail is rather intriguing, though, and the 
limbs are tall and rather slender.  I could see making an argument for a 
runner, but a tree-climber I dunno.

I'm so used to assuming slow speeds in the guys I work on, it's difficult 
for me sometimes to grant that, yes, some dinos were relatively fast 
critters or that not all may have lived on the ground.  Not remembering 
right now, but I'm pretty sure that Marasuchus has the ventrally-directed 
shoulder sockets, and so this would be another thing that would restrict the 
arms and make me have some doubts about it being a tree climber.

I guess I want to see more evidence for arms that could be pulled out 
sideways or more flexible limb joints.  The relatively high center of 
gravity would seem to make the animal vunerable to falling, and if a 
tree-dweller without flexible ankles and grasping feet, this would indeed be 
a bad thing. =)

One thing that has always intrigued me about dinosaurs is this idea: perhaps 
because they have relatively stiff joints and limbs that tended to move in 
relatively restricted planes, could this be a reason (among many) for why 
dinos got so big?  In other words, maybe one of the problems with getting 
huge is that if you have multiple degrees of freedom in your joints, you 
have problems going beyond a certain size because of all the torques, 
stresses, etc.  If you are ancestrally constrained, perhaps it is easier for 
you to get big?

I know this is not a completely original idea (and perhaps not original at 
all) but I know I've heard bits and pieces of these things somewhere before. 
 The point is, maybe it's not so bad to be a terrestrial stiff-legged 
"reptile": could have it's advantages, y'know? =) ;)

Matt Bonnan

"I've got two legs from my hips to the ground
And when I move 'em I walk around
And when I lift 'em they climb the stairs
And when I shave 'em they ain't got hairs
I've got two legs ..."
-- Monty Python

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