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Re: Vertebrae of Early Sauropods

Mike Taylor (mike@indexdata.com) wrote:

<The camellate condition is taken to the extreme in the vertebrae of
derived Titanosaurs such as _Saltasaurus_, in which the bone has
essentially the texture of a sponge, permeated by very many tiny bubbles. 
This is called the somphospondylous condition.  The same thing appears to
have evolved independently in _Mamenchisaurus_, so it may be a general
long-neck adaptation, and so less phylogenetically useful that it would
first appear.>

  Not to disagree with the premise here, but I would suggest that this not
be looked at so much as a long-necked adaptation, as titanosaurs typically
do not have very long necks, not so much longer than less than twice trunk
length, whereas diplodocids and "omeisaurids" have such a neck over twice,
and sometimes close to three-times, trunk length. Relatively
"short-necked" titanosaurids, like *Isisaurus colberti,* have
somphospondylous vertebrae, so this is a reasonable phylogenetic feature.
Titanosaur vertebrae are recognizable without this condition, as well.

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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