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Re: New in JVP
Jim Cunningham (jrccea@bellsouth.net) wrote:
<If from an adult Qsp, a 14 inch CV5 would equate roughly to a 4.35 foot neck
and a span of 14.2 feet, more or less. a 14 inch CV6 would equate roughly to a
5.04 foot neck and a span of 16.45 feet more or less.>
I've read the paper, now. Henderson and Peterson write (pg. 192):
"BMR P2002.2 resembles a putative fifth cervical of *Quetzalcoatlus* sp. from
the Maastrichtian Javelina Formation in Texas (TMM 42180-2), although BMR
P2002.2 possesses an apparently more robust hypapophyseal process (which
restricted ventral deflection of the neck) at its anterior end. We do not
attribute much importance to this difference, however, owing to the
substantial deformation suffered by both specimens. However, BMR P2002.2 is
relatively gracile by comparison with the Texas material. BMR P2002.2 is 348
mm in length (exapophyses to caudal condoyle) whereas the cervical of
*Quetzalcoatlus* sp. is 394 mm long. BMR P2002.2 is severely crushed
transversely and at midlength is only 5 mm thick. The corresponding
measurement of the dorsoventrally crushed TMM 42180-2 is 34 mm. The
distortion complicates comparison, but assuming a near circular cross
section
of both vertebrae, the diameter of the uncrushed Burpee Museum vertebra
would
have been about 18.25 mm at midlength whereas that of TMM 42180-2 was about
30.5 mm. The slenderness of BMR P2002.1 is also reflected by a transverse
diameter across the prezygapophyses of 22.25 mm compared to an estimated
width of ∼38 mm in the cervical of *Quetzalcoatlus* sp. (only one
zygapophysis is preserved in the specimen, and the anterior end of the
vertebra has been expanded transversely by crushing, preventing precise
measurement of its width). A comparable disparity in width exists at the
posterior ends of the specimens, but distortion precludes accurate
measurements. It seems unlikely that the difference in width between the two
vertebrae would have been eliminated by an increase in length of the BMR
P2002.2 specimen to equal that of the fifth cervical of *Quetzalcoatlus*
sp."
Thus Jim's surmise of generally a 5th cervical is borne out by the authors of
the paper. They state they studied the composite cervical series at the Texas
Memorial Museum, the same specimens Jim has, so it's no surprise there. The
crushing of the vertebra has collapsed the internal camarae so that only the
extremely thin walls of the bone define the width throughout most of the
vertebra.
Cheers,
Jaime A. Headden
http://bitestuff.blogspot.com/
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
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