Re: Notarium question

[David Peters <davidrpeters@earthlink.net>]

No, Jaime, I was referring to a _new_ bone. One _above_ the fused dorsals. 
Don't have the Renesto reference at hand. Will try to find.

David



"Jaime A. Headden" wrote:

> David Peters (davidrpeters@earthlink.net) wrote:
>
> <The pterosaur notarium articulation is a new structure, that is, one not
> present on Ichthyostega. I'm trying to think of other such examples in
> tetrapods, but I'm coming up almost blank.
>
> 1. That funny new bone on top of the dorsal hump on Megalancosaurus.>
>
>   Not sure this should be counted, or at least only with great
> reservations; the fusion of the distal ends of the neural spines of the
> second and third dorsals occurs only in *Megalancosaurus* among
> drepanosaurids, and only in the neural spines.
>
> <2. ???>
>
>   A functional equivalent occurs in other vertebrates where the vertebrae
> are not fused but are rendered virtually immobile, as in glyptodontids and
> other large xenarthrans, and birds; the vertebrae are fused into a single
> unit in turtles, as well, but this is the entire dorsal series through to
> the sacrum, so not sure if its analogous.
>
>   Cheers,
>
> =====
> Jaime A. Headden
>
>   Little steps are often the hardest to take.  We are too used to making 
> leaps in the face of adversity, that a simple skip is so hard to do.  We 
> should all learn to walk soft, walk small, see the world around us rather 
> than zoom by it.
>
> "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
>
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