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Re: Details on SVP 2001 Friday talks



First I want to thank all people who reported about SVP 2001.


And now, there were some interesting points in the phylogeny of theropods by Dr. Holtz:

A paraphyletic Ceratosauria, which Oliver Rauhut proposed already in 1999. More taxa means better resolution in cladistic analyses and thereby often showing that well-established monophyletic taxa are in reality paraphyletic. So which taxon may be next?

Siamotyrannus isn't inside Tyrannosauridae, but near Allosaurus and Sinraptor. Nice position because Buffetaut et al. stated in their discription of Siamotyrannus that sinraptorids have obturator notches, so they could hypothetically be ancestors of Siamotyrannus. (Of course they talked about tyrannosauroid ancestors because they regarded Siamotyrannus as the earliest known tyrannosaur.)

Eotyrannus as basal taxon inside Eotyrannus, I wonder if it helped move Tyrannosauroidae out of Maniraptoriformes?

Avimimus inside a clade (Segnosauria + Oviratorosauria), were the new findings of these recent Japanese expeditions to the Gobi used to recode Avimimus?

Troodontidae near Dromaeosauridae, so "sickle claws" stand united. I don't mean monophyletic, but who knows in a future analysis?

What surprised me was to see Scipionyx as most basal coelurosaur. IIRC it's a juvenile. May this basal position not be due to not having developed derived characters at this juvenile age, which otherwise would put it somewhere else in a phylogenetic analysis? Don't we see in this juvenile some kind of "common denominator" for coelurosaurian dinosaurs?

Cheers


Heinz Peter Bredow

BTW: I'm quite aware that everything may change with new analyses using new taxa and characters.


Mickey Mortime wrote:
>>
Holtz, 2001. Pedigree of the tyrant kings: New information on the origin and evolution of the Tyrannosauridae. JVP 21(3) 62A-63A.
Holtz had a phylogeny of theropods with 85 taxa and 642 characters with the following topology-
|-Herrerasauridae
`-+-Coelophysoidea
 `-+-Ceratosauria
   `-+-"Szechuanosaurus" zigongensis
     `-+-Spinosauroidea
       `-+-|-Monolophosaurus
         | |-Lourinhanosaurus
         | |-Sinraptor
         | |-Allosaurus
         | |-+-Fukuiraptor
         | | `-Siamotyrannus
         | `-+-Neovenator
         |   `-+-Acrocanthosaurus
         |     `-+-Carcharodontosaurus
         |       `-Giganotosaurus
         `-+-Scipionyx
           `-|-Compsognathus
             |-Nqwebasaurus
             |-Nedcolbertia
             |-Proceratosaurus
             |-Ornitholestes
             `-+-|-Stokesosaurus
               | |-Dryptosaurus
               | `-+-Eotyrannus
               |   `-+-+-Alectrosaurus
               |     | `-Bayn Tsav material
               |     `-+-Alioramus
               |       `-+-+-Albertosaurus
               |         | `-Gorgosaurus
               |         `-+-+-Daspletosaurus
               |           | `-new long snout taxon
               |           `-+-Tarbosaurus
               |             `-Tyrannosaurus
               `-|-Coelurus
                 |-Ornithomimosauria
                 `-+-+-Segnosauria
                   | `-+-Avimimus
                   |   `-Oviraptorosauria
                   `-+-Alvarezsauridae
                     `-|-Protarchaeopteryx
                       |-Troodontidae
                       |-Dromaeosauridae
                       `-+-Rahonavis
                         `-+-Archaeopteryx
                           `-Pygostylia
<<