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RE: JVP 27(1)



Justin Tweet wrote:

Butler, Richard J., and Upchurch, Paul. 2007. Highly incomplete taxa and the phylogenetic relationships of the theropod dinosaur Juravenator starki. 253-256.

A priori removal of seven taxa in the original description's tree (Göhlich and Chiappe, 2006) was
unjustified, and their results thus donot support Juravenator as a compsognathid, but they do support a basal maniraptoran position.

Butler and Upchurch's analysis does give the theropod tree a good shake. They do a lot more than simply dumping _Juravenator_ at the base of the Maniraptora. For example...


(1) _Allosaurus_, _Sinraptor_ and tyrannosaurids are recovered as a clade to the exclusion of coelurosaurs. This clade would fit Holtz's (2004) definition of Carnosauria. So, this analysis puts the Tyrannosauridae back among the carnosaurs! The Bremer support was weak, however. Also, only two derived tyrannosaurid taxa were used (_Albertosaurus_ and _Tyrannosaurus_), thus emphasizing the value of including basal taxa.

(2) An alvarezsaurid-therizinosauroid-oviraptorosaur clade pops up. This was recovered as the sister taxon to the Deinonychosauria-Aves clade.

(3) The analysis finds a _Compsognathus_-_Coelurus_ clade (Compsognathidae), that excludes not only _Juravenator_ (basal maniraptoran) but also _Sinosauropteryx_ and _Huaxiagnathus_ (both more derived than _Compsognathus_).

(4) _Coelophysis_ and _Dilophosaurus_ are recovered as consecutive outgroups to the Tetanurae. However, _Ceratosaurus_ and abelisaurids are conspicuous by their absence. (This could have impacted on (1) as well).

Cheers

Tim

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