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Re: My classification of coelurosaurs



  Just for everyone's information, there is no war between Ken
and I. I was annoyed the last time I wrote. As Ken said, there
was a New Year's Resolution on his part about PT. I made a
similar resolution not long ago to not reply in that manner. I
broke it. Appologies to Ken and the list. Meanwhile, this post
has absolutely nothing to do with PT, cladistics, PhyloCode,
etc....

  [we all cheer]

HP Ken Kinman (kinman@usa.net) wrote:

<For those of you who recognize a single clade for
Therizinosauridae, Caudipteridae, and Oviraptoridae---- you
would simply change the 9 to 8B (and then renumber 10-14 to
9-13). The capital letters indicate subclades (the main clades
are numbered in the order they split off). The coding symbol _a_
shows that Oviraptoridae is an exgroup from Caudipteridae. You
could combine them into an expanded holophyletic Oviraptoridae,
but I wouldn't recommend this (because it could become doubly
paraphyletic if the cladograms change significantly).>

  I respond to this only because it involves an area of research
for which I am quite familiar. Current anatomical systematics
and researches support the following tree (each node and branch
a distinct form with some ambiguity as to relationship -- some
groups have a lot of plesiomorphies, others are either extremely
derived, or not well described or known to clarify
relationships) -- there is some arbitrary choice in relationship
due to my own researches:

  --(unnamed taxon * ) (= Oviraptorosauria, sensu Padian et al.
     |                   1999)
     |--(unnamed taxon ** )
     |   |--*Beipiaosaurus*
     |   `--Therizinosauroidea
     |       |--*Alxasaurus*
     |       `--Therizinosauridae (= Segnosauridae,
     |                              Enigmosauridae)
     `--Oviraptorosauria (sensu Barsbold et al., 1990)
         |-?-Caudipteridae /*Caudipteryx*/
         |    |-?-*Microvenator* ( *** )
         |    `--*Caudipteryx*
         |-?-*Nomingia* (position not resolved beyond next node)
         |--*Caenagnathasia*
         `--Caenagnathoidea (= Oviraptoroidea)
             |--Caenagnathidae (= Elmisauridae)
             |   |--*Chirostenotes* (= *Caenagnathus*,
             |   |                    *Macrophalangia*,
             |   |                    Caenagnathiformes)
             |   `--*Elmisaurus*
             `--Oviraptoridae ( **** )
                 |--*Oviraptor*
                 `--*Ingenia*

Notes:
    *,a = The present definition for Oviraptorosauria supports
  inclusion of Therizinosauroidea, *Caudipteryx* and
  specifically all taxa closer to *Oviraptor* than to birds;
    *,b = a name has been floating around for a node
  specifically for the Therizinosauroidea + Oviraptorosauria
  node, so in a preemptive strike, I'm urging non-discussion of
  this name.
    ** = The name "Segnosauria" is available as the stem within
  the above (*,b) node; so instead of a new coin, reuse this
  one. Specifically avoids the problem of *Beipiaosaurus* being
  excluded from the Therizinosauroidea by definition, but still
  technically a segnosaur.
    *** = *Microvenator*, in answer to HP Mortimer's suggestion
  (or was this HP Tim Williams'? Tell me if you know who
  suggested this first, I forget) looks like a caudipterid to
  the exclusion of other similar taxa.
    **** = Several new taxa are being described, so this is a
  strict usage. Also, the taxon everyone thinks of as
  *Oviraptor* is not, but is rather restricted to the holotype,
  not the cassowary dino, and this form is close enough in form
  to "Rinchenia" that I think a more parsimonious relationship
  is them being congeneric, thus I abstain from the use of the
  name and hope it is not formally designated beyond Barsbold's
  (1997)use of it as a _nomen nudum_. As the only distinct and
  valid genera, the group is restricted to *Ingenia* and
  *Oviraptor.*
    Lastly but firstly, *Nomingia* is offered as a tentative
  caenagnathid (Barsbold et al., 2000a, and 2000b) based
  primarily on proportion and form of the hindlimb and the
  pelvis. These can be viewed as plesiomorphies to
caenagnathoids
  and the classification thus suggests it is not, but may be
  unresolved to the group. Or in other words, "I don't think
  it's a caenagnathid, but I don't know what the f*** it is."
    Lastly and lastly, *Caenagnathasia* is not a caenagnathid
nor
  a caenagnathoid: the form of the jaws is basal to both
  caenagnathids and oviraptorids. The similarities used to link
  *Caenagnathasia* to *Chirostenotes* are probably plesiomorphic
  unless tooth loss was convergent in oviraptorosaurs
  themselves, which argues against the collateral changes in the
  jaws seen in other members of the node == (Therizinosauroidea
  + Oviraptorosauria).

  I offer this as a clarification to the restriction of
Oviraptoridae as a reference taxon and the consideration of it
containing Caudipterydae, paraphyletic or holophyletic. The
situation is presently unresolvedly complicated. I've tried to
place *Avimimus* in reference to the paradigm, and this is quite
difficult without a relatively complete skeleton, such as the
one that Watabe and Sues, et al., are working on. HP Mortimer
offers a much more strict avian relationship. I'm going to shrug
on this one and let it pass. It is also possible *Elmisaurus*
and *Chirostenotes* represent regional variation that should
best be synonymized as *Chirostenotes* with subtaxa (species)
used to designate the elmisaur-like *E. elegans* and the
Mongolian and strict North American species. There are four
distinct forms I recognize that are probably not overlapping,
one being a North American form of the Mongolian taxon,
suggesting that Paul's (1988) position on synonymy might be
easier to take than the headache in resolving Currie's, Sues',
et al.'s relationships of the forms. As noted by HP Naish
(Naish, 2000), by Frankfurt and Chiappe (1999) and Currie, Rich,
and Vickers-Rich (1993) there are other forms scattered about
that may pertain to the strict or broad senses of
Oviraptorosauria. Relationships are far from clear.
*Caudipteryx* is placed below strict oviraptorosaurs because of
the consensus opinion: there are more strict oviraptorosaurian
features than there are general avian, or general
oviraptorosaurian features.

  Thus, the set may wish to reflect this by allowing other
exgroups:

Order Saurischiformes (in part)
              ......
      4   Allosauridae (= Carnosauria)
     5A   Ornitholestidae (possibly paraphyletic)
      B   Compsognathidae
      6   Tyrannosauridae
      ?   Coeluridae
      7   Ornithomimidae
      8   Therizinosauridae {{Oviraptoridae}}
      9   Caudipter(yg)idae
     _a_  Oviraptoridae
     _a_  Caenagnathidae
     10A  Alvarezsauridae
      B   Avimimidae
     11   Troodontidae
     12   Dromaeosauridae (= Deinonychosauria)
     13   Plesion _Rahonavis_
     14   {{Aves}}

  Tell me if I screwed up on this, Ken. I added a marker for therizinosaurids.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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