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Re: why isn't Tethyshadros insularis just a juvenile?



Just to underline two things:
FIRST: you all seem to forget that the specimen is an articulated skeleton
and is preserved on a slab of limestone. You cannot handle the bones.
When the state of preparation and preservation of the bones allow to check
it, the neurocentral suture is obliterated, both in Tethyshadros holotype and in
another specimen of the same size.

SECOND: there are very few methods to infere sexual maturity in an extinct
animal.

Cheers
Fabio

----- Original Message ----- From: "Jaime Headden" <qi_leong@hotmail.com>
To: "Denver Fowler" <df9465@yahoo.co.uk>;
<Dinosaur.Mailing.List@listproc.usc.edu>
Sent: Monday, December 14, 2009 11:36 PM
Subject: RE: why isn't Tethyshadros insularis just a juvenile?



Denver Fowler wrote:

<The neurocentral fusion is not addressed in the vertebral descriptions,
and is not confirmed histologically.>

My understanding is that generally taken, the obliteration or
near-obliteration of the suture between two bones is a proxy for complete
fusion. This is how vertebrae have been assigned "fusion" status for the
past, oh, 200 years. To histologically section -- or, perhaps favorably to
the preservation of the bones, CT -- each vertebra to compare the progress
of true fusion would be so time consuming and perhaps annoying if it would
need to be done for each specimen to assure oneself of IT'S age. This is
especially problematic when vertebral fusion may not actually infere
sexual maturity and/or "adult" status: It merely represents skeletal
maturity, which is most important in biomechanical aspects.

Cheers,

Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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