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Re: Sauropod Necks



At 05:08 PM 7/10/00 -0700, Matthew Bonnan wrote:
To continue an old thread further, a couple of points:

1. The horizontality of necks in sauropods has only been tested in the diplodocids Apatosaurus and Diplodocus. For those who don't already know, Mike Parrish, one of the two scientists who did these studies using the DinoMorph program (the other scientist is a computer programmer Kent Stevens), is my PhD advisor. I know they plan to do more with more sauropods, but at the moment, all we can say is that it appears that Apatosaurus and Diplodocus could not raise their heads past vertical.

I think you mean horizontal :-)

But I find it interesting that this condition is found in the sauropod group with the best anatomical adaptations for rearing up! (In this concept _Apatosaurus_ may have secondarily lost this ability, and be the one animal ever to actually use the vacuum cleaner mode of feeding).

Questions that need to be addressed include: how much rotation is possible of the femur in the hip socket of a sauropod? what muscles are involved and what landmarks can be used to verify that these muscle groups are indeed doing what we suggest? what effect does the large tail muscle (caudofemoralis longus) that pulls the femur back have on a rearing sauropod? did sauropods bend their knees when rearing, and if so, what sort of strain and stress did this send through their pelvis, hindlimb, and foot? sauropods have an open hip socket and a cylindrical femoral head: how was force transmitted through this during normal weight bearing, and could the pelvis and hindlimb handle rearing up? to name but a few that come to mind!

Not to mention issues of balance. Is the center of mass truly positioned over the fulcrum point?


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May the peace of God be with you.         sarima@ix.netcom.com