Titanoceratops, giant ceratopsian from New Mexico

[bh480@scn.org]

From: Ben Creisler
bh480@scn.edu

In case this new advance publication paper has not been 
mentioned yet:

Nicholas R. Longrich (2010)
Titanoceratops ouranous, a giant horned dinosaur from the 
Late Campanian of New Mexico.
Cretaceous Research (advance online publication)
doi:10.1016/j.cretres.2010.12.007 
http://www.sciencedirect.com/science?
_ob=ArticleURL&_udi=B6WD3-51TPVM1-
1&_user=10&_coverDate=12%2F29%
2F2010&_rdoc=1&_fmt=high&_orig=browse&_origin=browse&_zone
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4b09952a44a&searchtype=a


At the end of the Cretaceous, 65.5 million years ago, the 
giant ceratopsids Triceratops and Torosaurus dominated 
North America's dinosaur fauna. The origins of these 
giant ceratopsids, the Triceratopsini, are poorly 
understood. This paper describes Titanoceratops ouranos, 
a giant ceratopsid from the late Campanian (73-74 Ma) of 
New Mexico, and the earliest known triceratopsin. The 
holotype was previously interpreted as an aberrant and 
exceptionally large specimen of Pentaceratops sternbergi, 
but the animal does not show the diagnostic features of 
Pentaceratops. Instead, cladistic analysis shows that 
Titanoceratops is the sister taxon of a clade formed by 
Eotriceratops, Triceratops, and Torosaurus. With an 
estimated mass of 6.5 tons, Titanoceratops is the largest 
dinosaur known from the Campanian of North America, and 
rivaled Triceratops in size. The recognition of 
Titanoceratops suggests that giant chasmosaurines evolved 
once, among the Triceratopsini, and that the group 
evolved large size five million years earlier than 
previously thought. The giant horned dinosaurs probably 
originated in the southern part of the North American 
continent during the Campanian but only became widespread 
during the Maastrichtian.