Re: New dinosaur from South America

["TRUETT GARNER" <DINOBOY@worldnet.att.net>]

   Argentina has no monopoly on gigantic theropods . The king-sized
theropod trend seems to have started in the late Jurassic (Saurophaganax
maximus , ?Ceratosaurus ingens -USA and Africa respectively ) . By late
Early Cretaceous , giant theropods occupied 3 continents  , AFAIK ,
A.atokensis-USA , C. saharicus , Spinosaurus aegyptiacus (?) - Africa ,
G.carolinii and this new theropod-South America(I suspect that there is a
similar theropod in Asia , yet to be found) . In the Late Cretaceous we
have tyrannosaurs in N. America and Asia , Chilantaisaurus from Asia, and
to a lesser degree , size-wise , abelisaurs from the southern hemisphere
.All of these theropods had equally large contemporary herbivores in their
environment. Aside from that factor , what could provoke select theropod
groups to evolve to what must be the maximum size(40-50 ft.long) size for a
terrestrial predator ?
Interestingly , there seems to be no evidence for gigantic members of the
Coelophysoidea , or " megasaurs , AFIK .
Regards , 
Truett Garner