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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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