The East is Dinosaurian

[Dan Chure <danchure@easilink.com>]

A recent publication I haven't seen posted here yet.

Benson, R.B. and Xu, X. 2008. The anatomy and systematic position of the 
theropod dinosaur Chilantaisaurus tashuikouensis Hu, 1964 from the Early 
Cretaceous of Alanshan, People's Republic of China. Geological Magazine. 
doi:10.1017/S0016756808005475 Published online by Cambridge University 
Press 29 Aug 2008 
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=2171256

Abstract
There is little consensus on the systematic position of the colossal 
theropod dinosaur Chilantaisaurus tashuikouensis from the Cretaceous 
(Aptian–?Albian or Upper Cretaceous) Ulansuhai Formation of Inner 
Mongolia, which has been recovered as a derived member of both 
Allosauroidea and Spinosauroidea by numerical phylogenetic analyses. 
Redescription of the type material of C. tashuikouensis reveals an 
unusual combination of morphological features that render determination 
of its systematic position problematic. It possesses anatomical features 
that have been proposed as synapomorphies of Neotetanurae: a 
preacetabular fossa on the ilium, and a wedge-shaped cross-section of 
the shaft of the third metatarsal. It also shares some features with 
specific allosauroid taxa: a pronounced ulnar epicondyle on the humerus, 
and a prominent medial shelf bounding the preacetabular fossa on the 
ilium (also present in tyrannosauroids). However, it lacks some features 
that are present in all other allosauroids: a marked depression on the 
anterior surface of the distal humerus adjacent to the ulnar condyle, 
and a humerus that is less than 0.4 times the length of the femur; it 
furthermore possesses a tibial astragalar facet that is approximately 
10% of the tibial length, which suggests a more basal position within 
Tetanurae. Chilantaisaurus shares certain features with some 
spinosauroids: an enlarged and elongated first manual ungual, and a 
suprastragalar buttress that has been modified to a vertical ridge, but 
these characters are not unique to spinosauroids. A highly reduced 
fourth trochanter may be an autapomorphy of Chilantaisaurus, as has 
previously been suggested, or unite the taxon with Coelurosauria in an 
entirely novel grouping. On the basis of these observations it is likely 
that Chilantaisaurus is a neotetanuran, but unlikely that it is an 
allosauroid. Chilantaisaurus may belong to an alternative lineage of 
very large theropods that continued into the Cretaceous from the 
diversification of basal neotetanurans during the Middle Jurassic.

Dan Chure