[Taxacom] new phylogeny of early birds/coelurosaurs
kinman at hotmail.com
Sun May 20 17:19:38 CDT 2007
Phil Senter has published a new, expansive phylogenetic analysis of
primitive birds and other coelurosaurs. Although I have only seen the
abstract, I am particularly happy to see that his phylogeny does NOT show an
"enigmosaur" clade, and that therizinosaurs are more primitive than
oviraptorosaurs. Maybe the some of the guys on the Dinosaur Mailing List
will finally see why I argued so strenuously against an enigmosaur clade.
Senter's phylogeny also agrees with mine in that therizinosaurs (a.k.a.
segnosaurs) are the sister group to the clade which I call Class AVES. It
will be very, very interesting to see what characters in his analysis
support my broad Class AVES. The abstract is given below.
Senter, P. (2007). A new look at the phylogeny of Coelurosauria
(Dinosauria: Theropoda). Journal of Systematic Palaeontology.
Abstract: "The most comprehensive phylogenetic analysis of the theropod
clade Coelurosauria to date, is presented here, with 85 coelurosaurian
ingroups and 360 characters, using _Allosaurus_ and _Sinraptor_ as
outgroups. The strict consensus tree is highly resolved and has the
following topology: Tyrannosauroidea + (Compsognathidae + (Arctometatarsalia
+ (_Ornitholestes_ + (Therizinosauroidea + (Alvarezsauridae +
(Oviraptorosauria + (Avialae + (Troodontidae + Dromaeosauridae)))))))). The
analysis places _Coelurus_ and _Tanycolagreus_ at the base of
Tyrannosauroidea, _Deinocheirus_ within Arctometatarsalia,
_Protarchaeopteryx_ within Oviraptorosauria and _Epidendrosaurus_ at the
base of Avialae. The analysis results in wide phylogenetic separation
between _Caenagnathus_ (close to the base of Oviraptorosauria) and
_Chirostenotes_ (placed within a clade of crested oviraptorids), casting
doubt on their synonymy. All taxa with an enlarged, trenchant ungual on the
second toe are placed within Troodontidae or Dromaeosauridae; at the base of
the latter is an unenlagiine clade that includes _Unenlagia_ and
_Rahonavis_. The hypothesis that dromaeosaurids are secondarily flightless
birds is not supported."
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