Alamosaurus as biggest North American sauropod

[Ben Creisler <bscreisler@yahoo.com>]

From: Ben Creisler
bscreisler@yahoo.com
 
A new paper in Acta Palaeontologica Polonica:
 
Denver W. Fowler and Robert M. Sullivan (2011)
The first giant titanosaurian sauropod from the Upper Cretaceous of North 
America.
Acta Palaeontologica Polonica 56 (4), 2011: 685-690 
doi:10.4202/app.2010.0105
http://app.pan.pl/article/item/app20100105.html

Argentinosaurus (Cenomanian, Argentina) is generally accepted as being the 
largest dinosaur so far discovered and is one of several giant titanosaurian 
sauropods known from the Upper Cretaceous of South America and Asia, but 
surprisingly not from North America. Here we present the first evidence of 
giant titanosaurian sauropods from the Upper Cretaceous of North America: two 
enormous vertebrae and a partial femur, from the Naashoibito Member of the Ojo 
Alamo Formation, New Mexico, and referred to Alamosaurus sanjuanensis. One of 
the new vertebrae, a posterior cervical, is comparable in size to a posterior 
cervical described for Puertasaurus: an Argentinosaurus−sized titanosaurian 
from the Maastrichtian of Argentina. This makes A. sanjuanensis the largest 
dinosaur from North America, and among the largest in the world. These findings 
indicate that A. sanjuanensis is diagnosed based on immature remains, which may 
have implications for cladistic analyses.