Re: New Papers of the Ya-Ya Sisterhood

[David Marjanovic <david.marjanovic@gmx.at>]

> Smith's (2007) phylogenetic analysis removed _Acrocanthosaurus_ and 
> _Neovenator_ from the Carcharodontosauridae and put them both in the 
> Allosauridae (sensu lato).

The following SVP meeting abstract, also from this year, puts them back:

Stephen Brusatte & Paul Sereno: Phylogeny of Allosauroidea (Dinosauria: 
Theropoda): new analysis, comparisons, and sources of disagreement, p. 54A

Allosauroidea, a large-bodied clade of theropod dinosaurs ranging from the 
Middle Jurassic to the Late Cretaceous, has been the subject of several 
phylogenetic studies that have reached little consensus. We present a 
comparative cladistic analysis that attempts to integrate data from previous 
studies with new characters revealed by the description of several new 
allosauroid taxa from Africa and South America and the redescription of 
*Neovenator salerii* from the Early Cretaceous of England. First we review 
twelve previous studies of allosauroid phylogeny and discuss areas of 
topological disagreement. Second we compare our dataset to those of previous 
studies and evaluate the degree of overlap using novel comparative metrics 
that quantify shared character data. Our comparisons show that scoring 
differences, character choice, and taxonomic sampling are all major sources 
of incongruence. Importantly, numerous scoring differences highlight 
currently conflicting observations that must be resolved. Then we evaluate 
the status of the current understanding of allosauroid phylogeny and discuss 
the importance of rigorous comparative techniques in studies of dinosaur 
phylogeny. Finally we present our new analysis, based on 102 characters 
scored in 10 ingroup taxa, which represents the most extensive analysis of 
allosauroid phylogeny yet undertaken. The analysis strongly supports 
positioning *Sinraptor* as the basal-most [sic] allosauroid, *Neovenator* as 
the basal-most member of Carcharodontosauridae, and *Acrocanthosaurus* as a 
derived member of Carcharodontosauridae rather than a close relative of 
*Allosaurus*. This topology shows a strong overall match with the 
stratigraphic record, and cladistic biogeographic analysis suggests that the 
distribution of allosauroids is congruent with the breakup sequence of 
Pangaea.