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Re: Refurbished Berlin Brachiosaurus Mount
This is becoming tedious, Mike, but it is probably worth responding
to the DML.
First, you wrote in response to Jaime:
On Jul 19, 2007, at 1:08 AM, Mike Taylor wrote:
Jaime A. Headden writes:
Aside from the shoulder being 6m up, the head [of Brachiosaurus
brancai] is positionable at 9m IN ANY DIRECTION from the core of
the body, including parallel to the ground. This does not require
it to be vertical or even semi-vertical.
Of course. I am not aware that _anyway_ has ever argued that
Brachiosaurus was incapable of lowerig its neck to a horizontal
position! The question is whether it _all_ it could do, as Kent
That last sentence of yours is ungrammatical, namely: "The question
is whether it _all_ it could do, as Kent asserts." I hope you are
not suggesting that I am claiming that Brachiosaurus was incapable of
a reasonable range of dorsiflexion as well as ventriflexion. But to
ward off such a suggestion (and since it takes a lot of work to
correct misconceptions once they get out there, as in non-refereed
DML postings), let me quote two papers where what we put in writing
asserts what we meant to assert.
First, regarding neck ventriflexion of Brachiosaurus, Mike Parrish
and I wrote in our chapter in the Curry Rogers and Wilson (2005)
volume "Brachiosaurus could readily reach down to ground level
(without the need to splay its legs giraffe-style), provided it had
the modest ability to flex about 8 degrees ventrally in the proximal
cervical vertebrae" (p. 194), written in the context of discussing
overlap in vertical feeding envelopes across sauropod taxa.
Second, regarding neck dorsiflexion of Brachiosaurus, Mike Parrish
and I wrote in another sauropod book, the Tidwell and Carpenter
(2005) volume, that "While the range of dorsoventral movements
cannot be estimated due to the lack of preservation of the neural
arches, the head could reach over 9 m above ground level with a
modest dorsiflexion of approximately 3 degrees per joint" (p. 220)
We go on to conclude (p. 221) "It is not necessary to postulate
osteological adaptations, such as wedge-shaped centra, for
Brachiosaurus to have reached remarkable heights and to achieve a
huge feeding envelope, ..."
Got the idea? What Mike Parrish and I have written amounts to
saying: we envision no flexibility problem to prevent its head from
ranging from ground level (with a lot of competitive overlap with the
feeding envelopes of other sauropods such as camarasaurids, btw) up
to 9 m or so, which covers the great majority of all fodder. Once
again now: even if Brachiosaurus could raise its neck but a few
degrees dorsally it could reach 9 m.
But any scientific estimation of the range of motion will require a
specimen with intact neural arches. In the meantime, I hope people
stop suggesting that my colleague and I are saying things we never
did, such as "Diplodocus could not raise its neck" or (if my reading
of the above sentence is right) "Brachiosaurus could only lower its
neck". It doesn't serve any useful purpose that I can see for people
to trivialize work that has been carefully pursued and presented to
the scientific community with due caution and caveats.
The same is true for giraffes, which do not hold their necks
vertically (at least passively as extensively illustrated and
characterized for the bulk of sauropods).
I've often seen this asserted, to the point where it now seems like
orthodoxy. But whenver I see giraffes in a zoo, they are standing
with their necks near-vertical.
Mike, it might appear as "orthodoxy" to you when you see it
informally cited, but it is the result of scientific observations,
not just Sunday afternoon trips to the zoo. I point you to (Leuthold
and Leuthold, 1972; Pellew, 1984; Young and Isbell, 1991, Woolnough
du Toit, 2001). You can find these references in "Digital
reconstructions of sauropod dinosaurs and implications for feeding",
Kent A. Stevens and J. Michael Parrish, pp. 178-200, in The
Sauropods: Evolution and paleobiology, 2005 Kristina A. Curry Rogers
and Jeffrey A. Wilson, eds. Berkeley and California: University of
California Press, 349 pp.
/o ) \/ Mike Taylor <firstname.lastname@example.org> http://
)_v__/\ "If you're not sure what your options are, pop the ball in
net and we'll discuss it later" -- Bob Paisley.