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Re: Sauropod Necks



Matt et al,
Matt, you raise an interesting issue; I'm sure that in all sciences there is a greater level of skepticismm levelled at ideas that are aesthetically displeasing (whether due to true visual aesthetics, or "mere" philosophical sensibility). But I'm not sure that this is (entirely) the case with the sauropod neck stuff. For one thing, try to find a diplodocid reconstruction from a reputable paleo-artists from the last 10-15 years that show vertical necks. Bob Bakker did this with Barosaurus back in the 60's, but even he has been restoring diplodocids with horizontal for some time. The real debate with diplodocids has been over rearing, and although I rather strongly suspect they did, I agree that it needs to be better demonstrated.
While I can't speak for others, my concerns so far have only been over how to improve this impressive new tool, hopefully prior to widescale implimentation amoungst extinct taxa. And as I've said all along, I think the range of movement established in their studies are probably right. And they aren't all that radical, actually. The greatest degree of dorsaflexion shown in the studies are the same as or a little greater than the position Greg Paul has put them in (until recently, when he lowered the anterior cervicals a little). There was simply nothing controversial about it. The real "reach out and slap you" conclusion was the "neutral position" of diplodocids, which in artistic terms would refer to the pose of the neck while the animals were walking around. The results were that Diplodicus would almost have its chin graze the ground as it walked (ok, a slight exageration, I believe it was around .6 meters).
And here is where my real beef comes in: The concept of a "neutral" cervical position, and it being related to the normal position of the neck during locomotion. This was far and away the weakest supported part of the study, yet it is what truly decided the often discussed (maligned?) conclusion on diplodocid necks. What correlation is there between the neutral position and the common position? Horses, for example, spend much (possibly most) of their time with their heads near the ground while they eat, but when they travel, their heads are high atop erect necks, allowing them to scan for predators and obstacles in their path. Where would a horses neutral position be? High, low, or in the middle? I honestly don't know, but I wouldn't be suprised if a Dinomorph examined horse showed a neutral position in the middle of the horses' range of motion.
The Dinomorph project is a great tool, and with a little more grunt work to verify it, it may well become the premeire tool for range of motion studies for morphologists. But a heck of a lot more work needs to be done before the "neutral position" hypothesis can be born out, if it ever will in its current incarnation. Obviously Diplodicus didn't have it's neck sticking out at an angle like that of a horse. But considering the huge disadvantage the animal would suffer in terms of predator detection and obstacle avoidance with its head 2 feet off the ground, I would like to see much more thorough testing to convince me the head wouldn't be carried closer to the upper range of flexion demonstrated by Dinomorph.
Ok, that's my 3.5 cents.


Scott
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