Re: Long Bone Scaling in Neosauropod Dinosaurs

[Colin McHenry <cmchenry@westserv.net.au>]

Mike Taylor wrote:
> Colin McHenry writes:
>
>  >
>  > That's just so wierd.  If I didn't know any better, I'd say that
>  > the isometric scaling strongly suggested an aquatic habit....
>
> And yet isometry or near-isometry is much more common in limb bones
> that we'd naively expect.  McNeill Alexander, for one, has repeatedly
> made the point that the long bones of elephants are proportionally
> more gracile than those of much smaller rhinos and hippos. 

Isometry/allometry relate to within-taxon patterns of change-of-shape
with body size.  Your example could only be isometry if we were looking
at a very large scale analysis of  mammalian limb bones, and your
immediate problem would be that this example has cherry picked the three
'pachyderm' data points out of a much larger pool of taxa.

A better question would be, is long bone growth isometric with respect
to elephants?  Do adult elephants have long bones that are the same
shape as those  of baby elephants?  Are the long bones from small
elephants taxa the same shape as long bones from larger taxa?  (Does
anyone know?).

Likewise the earlier comments on 'stilt' like legs in humans, camels,
etc.  They may be stilt-like, but is growth isometric in these taxa?

Ok, I'm going to track down a copy of Matt's paper before I say anything
further!


Cheers
Colin




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Colin McHenry
School of Environmental and Life Sciences (Geology)
University of Newcastle
Callaghan NSW 2308
Australia
Tel: +61 2 4921 5404
Fax: + 61 2 4921 6925

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