Giganotosaurus

[tlford@ix.netcom.com (Tracy Ford )]

Where do I begin? Well, I went up to LA to Mary Odono's shop, she makes 
casts of fossil animals. Rodolfo Coria, and Phil Currie where there 
putting together the skull of Giganotosaurus (it's pronounced 
Jig-a-noto-saurus, with a hard J' in Jig, or more like an H), so Mary had 
a little get together with her paleo friends since both of Coria and 
Currie were there. They have more material of the skull, as well of the 
skeleton, of  Giganotosaurus now, premaxillae and the nasals. They were 
trying to get an estimated of the length of the skull. The problem is 
they had standard tape measure, but they use the metric system, luckily I 
had a metric tape measure. The skull, so far, is 165 cm long! And that's 
conservative! They know this because of the different bones of the skull 
they have. The drawing I did of the skull of Giganotosaurus, which I 
modeled after Abeliasaurus, was close, but still not correct. I had the 
braincase at an angle. Coria said to level off the braincase, but in 
doing that the quadrate would be at a 45 degree angle (or so) to the top 
of the skull, which is correct. So, some of the length of the skull is 
just the quadrate from the top of the skull to the dentary. Still it's 
bigger than T. Rex and yes bigger than the new skull of 
Carcharodontosaurus. Phil said that the premaxilla of the 
Carcharodontosaurus, which isn't known, is drawn to long (which is 
another thing I have to correct on the Giganotosaurus skull), so instead 
of  Carcharodontosaurs being 163 cm, it should be 152 cm long.  The 
occipital condyle of Giganotosaurus is near the top of the skull, which 
is strange. It's not very high, but wide. The nasals are heavily regouse, 
it had many small nobs and valleys. Phil said that some believe that 
there was a horny sheath over the nasals (which I've heard mentioned 
before) which would exaggerate the nobs. In Alioramus there would be 
about 6 horn's on the nasals. I think Phil is leaning toward that. Coria 
showed a slide of a dentary that was found 80 years ago that is nearly 
identical to that of the type of Giganotosaurus, but is 10 percent 
bigger! Phil and Coria believe that Carcharodontosaurs and Giganotosaurus 
are related to each other, also Ableisaurid's and Sinraptorids. Coria and 
Currie will be doing a paper on it later this year. 

The skull, when complete will be cast and the casts will be for sell, and 
in pieces.

They have nearly the complete  vertebral series of Giganotosaurus now. 
All the cervical vertebrae save the axis. The neck is short, but the 
skull is long, which Phil wasn't surprised about. The skull got bigger 
while the neck got shorter.  More dorsals, and the complete caudal series 
is known. 

I now know just how the skull of theropods fit together. Phil showed 
everyone. He showed just how the nasals fit into the top of the maxilla 
and the lachrymal. He talked about the kinetics' of the skull. The 
question on the `bite' of Giganotosaurus and Tyrannosaurs came up. The 
teeth of Giganotosaurus are for tearing and ripping while Tyrannosaurus 
is for bone crushing and cutting. The function of the serration's of the 
teeth were explained. The outer serration's actually `grab' and pull the 
skin, muscle fibers, while the inner part of the serration's has the 
razor sharp edge, which does the cutting, much like the electric shaver 
commercial that says it lifts and cuts. In Giganotosaurus the teeth are 
thin and have a thin serration,  while in Tyrannosaurus, the serration's 
are wider (the teeth have a larger diameter) for bone crushing, but also 
have that razor edge between the serration's.

During the slide show Coria showed a nodosaur femur recently found in 
Argentina. He said that after scouring the museums for Titanosaur dermal 
scutes, they found nodosaur scutes also. The new dryosaur/camptosaur 
(Gasparinisaura) leg was shown. It's complete, and even shows has 
metatarsal 1 behind metatarsal 2! It's a very small animal. Also a 
fragment of maxilla and dentary of an Iguanodontid. 
Coria will go out the Giganotosaurus quarry to hopefully find more 
material. The bedding plane is sloping slightly down into a hill. 

Amaragasaurus was brought up, and Coria and his colleagues believe that 
there was no connective tissue and may have had just a skin covering the 
`spines' or a horny sheath. I asked about the dermal scutes of 
titanosaurids, were they in  2 rows, like I've seen or like Mark Hallet's 
drawings of a body covered by it. Coria had a alternative theory. He said 
that when the embryo was developing, the top of the neural spine 
`pinched' off, then had a layer of skin develop in-between the scute and 
spine. So in life there would be only one row of scutes over the top of 
the neural spines! Also, it turns out, Herrasaurus had the same thing! 
Herrasaurus had dermal scutes! I asked about the teeth of Titanosaurids, 
which have both spade like and pencil like teeth. Coria said the `pencil' 
like teeth have a smaller diameter than the `pencil' like teeth of 
Diplodocid's. Also in Diplodocid's the teeth are in the front of the jaws 
while in Titanosaurids, the teeth fill the jaws. Apparently they ate 
similar food, but that's all. Titanosaurids are Brachiosaurs, or more 
correctly, a subfamily of Brachiosauridae.

Phil said that at Dinosaur Provincial Park, he's going to do a paper on 
the birds from there. There are bird teeth, one belonging to a large 
Hesperornitid, and a `modern' bird the size of an eagle. Also, he has a 
good otonogentic series of Albertosaurus ( from a small individual, which 
doesn't have Aublsyodon teeth) and Daspletosaurus.

I can't think of anything else except for the invertebrate people out 
there, there is a carapace of a spider about 18 to 24 inches from the 
Permian in Argentina! WOW!!!

Tracy