Re: [Re: Sauropods and lung development]

[archosaur@usa.net]

Another strange thing about Plesiosaurs is that they had platycoelus vertebrae
which had to put a hamper on neck mobility. 

Perhaps instead of opting for procoelus or opithicoelus they just added more
verts on to compensate.

Good ole evolution at it again.

Archosaur J

http://members.tripod.com/~jurassosauridae/index.html

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> Betty Cunningham wrote:

> 

> <How does the vertebrae count of long-neck plesiosaurs compare to

> sauropods?>

> 

>   Oh, let's see, about 50 in *Plesiosaurus*, and about 14 in

> *Diplodocus*? The numbers may be off by one or two, though, but the

> ratio between the two is still incredibly high, in the plesiosaur's

> favor. The vertebrae are more simplistic on plesiosaurs, as well,

> without the complext external excavation or structs, because support

> of mass on the surfaces are reduces, which is really what the external

> struts are for: as in a skyscraper or column, the external ribbing and

> cross-hatching and fluting are designed to hold shape and support the

> mass from one point to another.

> 

>   My opinion is that sauropods possessed the external (note, not

> internal) supports to keep their vertebrae's shape as they elongated.

> Plesiosaurs did not elongate the vertebrae, so increased their number.

> Sauropods, it seems to me, tried to make due with what they had,

> adding a vertebrae every so often in their evolutionary development

> when it was nessessary to extend the scope of their niche, or exploit

> a new one.

> 

>   Or so I think.

> 

> ==

> Jaime A. Headden

> 

> Qilong, the website, at:

> http://members.tripod.com/~Qilong/qilong.html

> ---

> All comments and criticisms are welcome!

> 

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