Re: Sauropod Necks

["Scott Hartman" <scott_hartman@hotmail.com>]

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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