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Re: sauropod necks-buckaroobwana is back! ha ha ha ha ha !!
This has probably been discussed before, but could sauropods raise their
necks up into a vertical position?
Yes, many times. As Justin Tweet already mentioned, work by my advisor (J.
Michael Parrish) and Kent Stevens (who programmed DinoMorph, the program
which allowed them to articulate the vertebrae in cyberspace) has shown that
the diplodocids Apatosaurus and Diplodocus could not raise their necks
beyond a horizontal position. This is so because the zygapophyses (the bony
joints between the vertebrae, not to be confused with the vertebral discs)
lock up when the cervical (neck) vertebrae are raised into a horizontal
position. The computer model essentially modeled these joints based off of
careful measurements of the zygapophyseal surfaces by Parrish and Stevens on
Diplodocus and Apatosaurus specimens.
There appears to have been a surprising amount of lateromedial (side to
side) motion in the necks of these guys, however, and Apatosaurus can
ventriflex (bend its neck downward) its neck such that its head would be
looking underneath its feet! Of course, this is only possible in cyberspace
with no ligaments, muscles, and connective tissues accounted for, but the
downward flexibility of the neck in diplodocids is extraordinary. This
suggested to Parrish and Stevens that diplodocids may have been grazers.
In Camarasaurus, the jury is still out. Parrish and Stevens tried a
preliminary attempt at modeling that neck, but the darn thing did not seem
to want to get above horizontal either. However, they are currently looking
this over, as it seems that Camarasaurus may have had a more vertical neck.
Brachiosaurus did have a relatively vertical neck, but not as tightly kinked
a one as you see in most illustrations (e.g., Greg Paul's Brachio herd or
muscle restoration pics show the neck much too vertical -- in those
positions, the vertebrae are literally disarticulated from one another --
just an example, not to pick on Greg Paul who, in my opinion, is a fantastic
As far as endothermy/ectothermy in sauropods, well, who knows? We don't
have the information or complex enough computers to accurately model
physiology in living archosaurs, let alone sauropods. The current evidence
seems to suggest that dinosaurs grew fast, but we also see LAGs (lines of
arrested growth) in dino bones as well, a trait not usually seen in
endotherms but seen commonly in ectotherms. In any case, perhaps sauropods
and most dinosaurs were in a physiological category by themselves. I tend
to think dinosaurs were endothermic but only in terms of muscle energy and
in terms of having more fine control over their homeostasis than, say, a
I would doubt sauropods were "hot-blooded," high-speed critters, but I would
also doubt sauropods were simply big "cold-blooded" archosaurs maintaining
constant heat through bulk. Bulk homeothermy, as well as Bakker et al.'s
dinosaur endothermy, seem to be too simplistic of concepts for temp control
and physiology in dinosaurs. Plus, it's difficult to devise tests for these
sorts of questions. Unfortunately (and I mean this -- I wish I had a time
machine to solve this whole mess), we have not yet hit on a way to ascertain
with a rigorous degree of certainty the physiology and metabolism of
Hope this helps,
A number of books by Knut Schmidt-Nielsen deal with animal energetics and
physiology, and you may wish to visit your local library to check these out.
Schmidt-Nielsen is probably one of the best popularizers of animal
physiology and metabolism, and is a good place to start.
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