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Re: Species & Giraffe necks



In a message dated 4/12/99 8:15:47 AM EST, th81@umail.umd.edu writes:

<< Solounias, N.  1999.  The remarkable anatomy of the giraffe's neck.  J.
 Zoology 247:257-268.
 
 >From the Summary:
 "Each of the mammalian cervical vertebrae C6 and C7 and thoracic vertebra
 T1, possess several distinguishing characteristics.  In the giraffe, these
 three vertebrae and their associated soft tissue structures are identical to
 other mammals but are displaced posteriorly by one vertebral position.  Many
 morphological conditions (characters) including vertebral morphology, longus
 colli and longus capitis muscles and the configuration of the roots of the
 brachial plexus support this finding.  Thus, the first thoracic of the
 giraffe (vertebra number 8) is morphologically equivalent to the seventh
 cervical vertebra, and the second thoracic (vertebra number 9) is identical
 to the first thoracic of other mammals"
 and
 "The first rib is unusual in articular position and in relation to
 surrounding structures and attaches on C7 (vertebra number 8), masking the
 recognition of the true C7." >>

I sincerely hope that the author actually >counted< all the presacral 
vertebrae of the giraffe and found one more than usual in other giraffids 
(extant and fossil). If there is >no< new presacral vertebra, then I'd say 
it's more likely that some of the features of the cervicals simply shifted 
backward one unit than that a new vertebra appeared in the neck while another 
coincidentally disappeared from the back. This is supported by the author's 
inability to recognize the location of new cervical vertebra ("between C2 and 
C6"). But then again, I haven't read the paper, and I don't know much about 
giraffe anatomy, either.