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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 asserts.

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 <mike@indexdata.com> http:// www.miketaylor.org.uk
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