Re: Introducing Mahakala omnogovae, little dromaeosaurid of Mongolia

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

----- Original Message ----- 
From: "Thomas R. Holtz, Jr." <tholtz@umd.edu>
Subject: Introducing Mahakala omnogovae, little dromaeosaurid of Mongolia

> Inclusion of the data into the latest AMNH Theropod working group matrix
> reveals it to be the basalmost dromaeosaurid, despite its age. More 
> derived
> dromaeosaurids are better resolved phylogenetically than earlier versions 
> of
> this matrix: a clade comprised of Unenlagiinae (Shanag + Buitreraptor +
> (Rahonavis + Unenlagia)) + Sinornithosaurus + Microraptorinae (Microraptor
> gui + Microraptor zhaoianus + Graciliraptor), and a clade of "classic
> dromaeosaurids": Velociraptorinae (Tsaagan + (Saurornitholestes +
> (Velociraptor + Deinonychus))) + Dromaeosaurinae (Adasaurus + 
> Dromaeosaurus
> + (Achillobator + Utahraptor)).

The resolution is further increased by the fact that the tree in the paper 
is not the strict consensus. It is the Adams consensus (of 1296 trees). 
Supplementary information, p. 27: "Strict consensus differs in reduced 
resolution within the *Adasaurus*, *Dromaeosaurus*, *Achillobator*, 
*Utahraptor* clade due to lability in placement of *Dromaeosaurus*; reduced 
resolution within the *Unenlagia*, *Rahonavis*, *Buitreraptor*, *Shanag* 
clade due to lability in placement of *Shanag*; and reduced resolution 
within the oviraptorosaurs more derived than *Incisivosaurus gauthieri*."

The Velociraptorinae-Dromaeosaurinae split is real, though, and so are the 
positions of *Jeholornis* and *Jinfengopteryx*.

> Given the size of the basal members of each clade ((Archaeopteryx +
> Jeholornis) + Pygostylia);  (Mei + Sinovenator) + Jinfengopteryx; 
> Mahalaka),
> the basal eumaniraptoran would seem to be a small Archaeopteryx-sized
> critter.

Not just "seem". They calculate that using a sophisticated method that is... 
completely different from that used in Laurin 2004 (body size evolution of, 
uh, limbed vertebrates, Devonian to Middle Permian, Systematic Biology) and 
my M.Sc. thesis. :-o Will be interesting to compare. It apparently doesn't 
take branch lengths into account.