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Re: What is a "shoulder vertebra"?

Mike Taylor (mike@miketaylor.org.uk) wrote:

<In older literature, I have occasionally come across mention of a "shoulder
vertebra".  Does anyone know whether this is, or was, a formal term, or merely
descriptive?  Clearly it's from somewhere in the region of the cervicodorsal
transition, but does it correspond to what we would call the last cervical or
the first dorsal?>

  This refers to what Sam Welles called a "pectoral" vertebra, or basically a
transitional vertebra between the cervical and dorsal series. These vertebrae,
in which animals possess a distinct morphology, will tend to have larger
hypapophyses, diapophyses with a moderate lateral orientation, parapophyseal
facets on the neural arch/centrum transition, etc. This morphology tends to
appear in theropods for the most part, as most ornithischians and virtually all
sauropods lack a transitional element between cervical and dorsal series.

  I hope this helps,


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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