eumaniraptoran systematics (was Re: Revising Hou et al, 96 (very very long))

["T. Michael Keesey" <mightyodinn@yahoo.com>]

----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
Sent: Wednesday, April 24, 2002 8:01 AM
Subject: Re: Revising Hou et al, 96 (very very long)
 
>   Presently, I'd say this character supports *Sinornithosaurus* as a
> stem-dromaeosaurid (needs a name, and under current convention, the name
> Dromaeosauroidea would seem applicable [*Dromaeosaurus* + oides {grk.,
> form}, lit., the form of *Dromaeosaurus*

Now that troodontids do seem to be deinonychosaurs (thanks to _Sinovenator
changii_), perhaps some of the definitions should be re-thought. It would be
nice to have a node-based taxon for Clade(_Troodon formosus_ + _Dromaeosaurus
albertensis_).

Currently we have (unfortunately doing all from memory -- corrections are
extremely welcome):

_Eumaniraptora_ Padian, Hutchinson & Holtz 1998 (emended for PhyloCode) =
Clade(_Vultur gryphus + _Deinonychus antirrhopus_)

_Avialae_ [Gauthier 1986] Padian 1997 (emended for PhyloCode) = Clade(_Vultur
gryphus_ <-- _Deinonychus antirrhopus_)
(also defined in Gauthier 1986 as Clade(_Archaeopteryx_ + _Neornithes_) and in
de Queiroz & Gauthier 2001 as Clade("wings used for powered flight" in _Vultur
gryphus_))

_Deinonychosauria_ [Colbert & Russell 1969] Gauthier 1986 (emended for
PhyloCode) = Clade(_Deinonychus antirrhopus_ <-- _Vultur gryphus_)
(also defined in Sereno 1998 as Clade(_Deinonychus_ + _Troodon_).)

Troodontoidea [Gilmore 1924?], not explicitly defined

_Troodontidae_ [Gilmore 1924] Sereno 1998 (emended for PhyloCode) =
Clade(_Troodon mongoliensis_ <-- _Dromaeosaurus albertensis_) 
(I COULD WELL BE WRONG ON THIS ONE; also, IIRC, Varrichio 1997 (in Currie &
Padian) suggests a stem-based taxon with other coelurosaurian lineages as
outgroups.)

Dromaeosauroidea [??], not explicitly defined

_Dromaeosauridae_ [not sure -- Matthew & Brown 1922?] Currie & Padian 1997
(emended for PhyloCode) = Clade(_Dromaeosaurus albertensis_ + _Velociraptor
mongoliensis_)
(I think Sereno 1998 defined it as Clade(_Dromaeosaurus_ <-- _Troodon_), but
could be wrong.)

_Dromaeosaurinae_ [??] Currie & Padian 1997 (emended for PhyloCode) =
Clade(_Dromaeosaurus albertensis_ <-- _Velociraptor mongoliensis_)

_Velociraptorinae_ [??] Currie & Padian 1997 (emended for PhyloCode) =
Clade(_Velociraptor mongoliensis_ <-- _Dromaeosaurus albertensis_)

Applied to the most widely-used phylogenies:

--Eumaniraptora
  |--Avialae
  |  `--Vultur gryphus
  `--Deinonychosauria
     |--Troodontidae
     |  `--Troodon mongoliensis
     `--Dromaeosauridae
        |--Dromaeosaurinae
        |  `-Dromaeosaurus albertensis
        `--Velociraptorinae
           |--Deinonychus antirrhopus
           `--Velociraptor mongoliensis

Although many researchers use "dromaeosaurid" (or even "dromaeosaur", despite
there being no "Dromaeosauria") for the stem-based group Clade(_Dromaeosaurus
albertensis_ <-- _Troodon mongoliensis_), but the name _Dromaeosauridae_ was
applied by Currie and Padian to a more restricted node within.

I see two possibilities here.

1) Go with Sereno's recommendation (if I am recalling it correctly) and make
_Troodontidae_ and _Dromaeosauridae_ stem-based clades. Dromaeosauroidea (or
Troodontoidea, whichever has priority) could then be used as for the node
(_Dromaeosaurus albertensis_ + _Troodon mongoliensis_) (equivalant to Sereno's
_Deinonychosauria_), and _Dromaeosaurinae_ and _Velociraptorinae_ could
continue to be used in their current fashions.
DRAWBACKS: No name for Clade(_Dromaeosaurus albertensis_ + _Velociraptor
mongoliensis_). Could make it _Dromaeosaurinae_,and use Dromaeosaurini and
Velociraptorini for what are currently _Dromaeosaurinae_ and
_Velociraptorinae_, but that goes against current usage.

2) Use Jaime's suggestion and make Dromaeosauroidea a stem-based sister to
_Troodontidae_. Actually, it might also be nice to call Clade(_Troodon
mongoliensis_ <-- _Dromaeosaurus albertensis_) Troodontoidea, and make
_Troodontidae_ a node within it -- say, Clade(_Sinornithoides youngi_ +
_Troodon mongoliensis_)? (And then we could also have _Troodontinae_ as
Clade(_Troodon mongoliensis_ <-- _Sinornithoides youngi_).)
DRAWBACKS: No name for Clade(_Troodon mongoliensis_ + _Dromaeosaurus
albertensis_). Of course, since there aren't any known members of
_Deinonychosauria_ which are not thought to be in this node-based clade, ti
probably doesn't matter much for now, although it might someday.

#2 seems preferable to me. It might also be wise to replace the _Troodon_-based
names with _Saurornithoides_-based names, as _Troodon_ may be a _nomen dubium_.
(Saurornithoidoidea sounds kinda weird, though, doesn't it?)

Okay, back to work I go -

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