| Gettin Gigi With It: Part 2
I'm going to make amends and say that in taking another look at my pictures of the top of the skull... I don't think that the epaxial muscle go as far forward as I first thought. They might have cut downward at a sharp angle. It still looks like it went the way that I mentioned above, but didn't extend as far... Maybe to about midorbit on the dorsal surface of the skull? I gather it could have been that the neck was held at a lower angle, and the skull was angled up more at this point. This is completely different from Tyrannosaurus rex if this was the case. And actually, I found a drawing by Paul and he does put the vertebrae lower and the head higher. And I'm willing to go out further on a limb and say that the cervical vertebrae of Giganotosaurus remind me of an opossum's. A friend was telling me that in an opossum, the neck vertebrae have neural spines that are thick and in a way relatively tall... and they all line up very close, supporting each other. They are also square in their cross section. Opossum cannot move their heads very well, and when they do, they move it very slow. They simply do not have a great range of motion to play with. Of course, there are still the interlocking differences in Giganotosaurus that the opossum does not have. The interlocking in Giganotosaurus are really just very robust zygapophysis? Zags are usually found at the junction of the lamina and the pedicel of the neural arches, the bottom part of which is usually the transverse process, or the diapophysis. This articulates with the dorsal part of the rib, or tuberculum. The parapophysis on the lower part of the vertebrae itself articulates with the capitulum of the rib... the lower part of the fork. They just appear to be so close in Giganotosaurus... all built in a manner to support one another... all interlocking. Of course, as they get bigger in Tyrannosaurus rex, the parapophysis also appear to become more supportive as well.... but they don't interlock to the same degree as in Giganotosaurus. And what's interesting is that in the aforementioned drawing from Paul, the cervical ribs almost look as if they lie on top of one another.... like a support system for the zags above them. It's like a sauropod actually. Each zag supports the one in front of it and behind it. There is very, very little in the way of comparative flexibility here with that of Tyrannosaurus rex. In all, it could mean that the twisting range in the head of Giganotosaurus would have been greatly reduced, but this is no big deal. Birds tend to lose that in a lot of ways past the atlas axis complex point. Tyrannosaurus rex's neck isn't even close to this. It's strong, but seems to be able to move through a range of motion. Like I said in my original post..... the pulling method of biting. Tyrannosaurus rex could have done this with the neck alone, coupled with the body. Giganotosaurus?..... It would have had to of bitten, and then pulled back with its legs... and this really doesn't look good for its weaker teeth. Going through flesh?.... Sure..... But, forget bone and even strong connective tissues. And really, this does make sense if you look at the dominant prey animals in both of these animals' habitats. Big, meaty sauropods for Giganotosaurus. And for Tyrannosaurus rex... I can only say hadrosaurids and ceratopsians loaded with ossified tendons and whatnot that just made them look to be full of what I can only call lots and lots of gristle. So, I'm thinking that the head of the cervical ribs may have acted like an interlocking brace with Giganotosaurus... and in Tyrannosaurus rex they were much more gracile. Since I don't have my very own Tyrannosaurus rex at my disposal, looking at only pictures, it appears that the main strength of Tyrannosaurus rex's cervical vertebrae were from the centrum themselves. It's hard for me to tell what's going on with them since I can't get a good view of the bodies of the vertebrae themselves. I don't have any good views from below.... and the dorsal structures give a nice mirage of robustness to them. BUT... as far as I can tell, the cervical vertebrae on Tyrannosaurus rex are in a relativistic way, wider than that of Giganotosaurus.... and they would be the main place where the force was taken up. As I've been saying, Tyrannosaurus rex just doesn't have anything near the interlocking mechanism that is found in Giganotosa! ur! ! us. It mostly just has the pre and post zags, and there is no body to the zags that would brace the other zags in front of or in back of each other. And the heads of the ribs are not formed into any type of brace either.... They do not really contact. They would have overlapped, but they are thin.... and obviously did not form the support like in sauropods. Of course, it's easy for me to see pre and post zags if looking at them from the right angle... But those of you that work directly with these animals know that they have accessory articulation points as well. All terrestrial tetrapods vertebrae have them. I could be getting carried away with accessory ones too... or not even seeing those that exist. The things are usually buried between the zags. And that's that. I think I've spent way too much time on this.....In vain?.... So, I'll be drinking Friar Tuck's ale and partying with Maid Marian if anyone needs me...... Kris |