About abelisaurs

[Amtoine Grant <ajgrant@eastlink.ca>]

As I'm trying to figure out the likely methods of attack various 
lineages of theropods may have used, I find myself contemplating on the 
the abelisaurs. I've read that the lower jaw of at least Carnotaurus 
seems 'weakly' built with more slender than usual teeth. To me, it 
would seem that the jaws may not have been the best method of attack. 
But the arms are atrophied as if attempting to make a two-legged snake. 
.
Which brings me to the feet. Noting the strange structure of the 
foremost caudal vertebra, perhaps this may have been  an adaptation to 
balancing on the tail while striking with the toe claws. . Are toe 
claws known for abelisaurs?
I was originally thinking that they may have been leapers, leaping and 
ripping at the fleshy necks of sauropods, a feat for which they would 
not have needed particularly strong jaws. Perhaps the 'wing'-shaped 
dorsal vertebrae were an adaptation for withstanding the stress to the 
backbone when landing from these leaps. .
Also, I've noticed that the cranial morphology of 
abelisaurs(Carnotaurus at least), compared to all other predators in 
the animal kingdom, most closely resembles piranhas[albeit 
superficially]. .
Thoughts?

BTW, watching the Alpha's Egg episode of Dinosaur Planet, did anyone 
else notice that they had Carcharodontosaurs attacking the sauropods in 
South America? Last I checked, Carcharodontosaurus is from Africa, 
Giganotosaurus is from South America. LOL