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RE: Talluscoatum and Maniraptoran Tyrannosaurs



From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Nicholas Gardner
My response to Dr. Holtz: (his text is preceded by ">>")
 
 > Microvenator is a possible member of the Elmisauridae which is what I seem to pick up from other  
> dinosaur sites. Caenagnathus is not a valid taxa whereas Elmisaurus is therefore the clade should be  
> renamed to fit valid internal members.
 
Although Caenagnathus itself is not a valid taxon name (it seems to be a junior synonym of Chirostenotes), Caenagnathidae is the accepted name of the taxon comprised of all oviraptorosaurs closer to Chirostenotes than to Oviraptor.
 
Although there is little preserved in Microvenator, there do not seem to be derived caenagnthid/elmisaurid features in it. I wonder if people placed it there on their websites under the premise "its primitive, elmisaurids are primitive (?!?!), so it must be an elmisaurid".  Oviraptorosauria incertae sedis is probably  teh best for present.
 
 > About the "coelurid-grade forms",  do you mean the ornitholestids and Coelurus?  I'm still working on the  
> troodontids (actually, I forgot to put them in the when I wrote my post).  They could be dromaeosauroids,  
> birds (?), arctometatarsalians or "enigmosaurs".  Personally, I think they may be somewhere between birds  
> and dromeys.
 
>Agreed to all of the above.  Troodontids do seem to bop all over the cladogram, but seem to be settling in Paraves, and maybe within Eumaniraptora.
 
>>You are mistaken about the wrist morphology of ornithomimosaurs.  Their carpals are >>NOT re-expanded: they are instead reduced relative to the condition in typical theropods >>OR more derived maniraptorans.
 
 > I just meant that...No wait, I'm confused and mistaken.  And you are right on that.  I guess working in a  
> museum and being a professional paleontologist gives you access to stuff I only can find in books or on the  
> internet.
 
True. 
 
REVISED CLASSIFICATION
 
--Maniraptora
  |--"Enigmosauria" Keesey, unofficial
  |  |--Oviraptorosauria
  |  |  |?-Caudipteryx
  |  |  `--+--Avimimidae
  |  |     `--Oviraptoroidea
  |  |        |--Elmisauridae
  |  |        |  `--+?-Microvenator
  |  |        |     `--(others)
  |  |        `--Oviraptoridae (sensu J.A. Headden, DML)
  |  `--Therizinosauria
  |     |?-Beipiaosaurus
  |     `--Therizinosauroidea
  |        |?-Alxasaurus
  |        `--Therizinosauridae
  |           |?-Nothronychus
  |           |--Segnosaurinae (?=Enigmosaurinae)
  |           |  |--Enigmosaurus
  |           |  |--Erlikosaurus
  |           |  `--Segnosaurus
  |           `--Therizinosaurinae
  |              |--Nanshiungosaurus
  |              `--Therizinosaurus
  `--Eumaniraptora
     |?-Troodontidae
     |  |--"Archaeornithoidinae"
     |  |  |--Archaeornithoides
     |  |  `--Byronosaurus
     |  `--Troodontinae
     |     `--+--(others)
     `--+--Aves
        |  |?-Alvarezsauridae
        |  `---->Pygostylia
        `--Dromaeosauroidea (implied Matthew & Brown, 1922)
           |--Archaeopterygidae
           `---->Dromaeosauridae
 
I like it.  I'd also like to say that Archaeornithoides and Byronsaurus may indeed be very closely related, but more work needs to be done.
 
 > There for now, I hold this view but I don't know what to do with everyone coelurosaurs, especially the  
> dryptosaurids, coelurans, ornitholestids, compsognathids, tyrannosaurs and ornithomimosaurs.  I think  
> Sereno's Tyrannoraptora might be reworkable...
 
Actually, Sereno's Tyrannoraptor is Tyrannosaurus + Neornithes.  In many recent phylogenies, this clade would contain Maniraptoriformes: it might also contain some of the taxa you mention.
 
 > Just one last thing, though...  WHAT ABOUT TALLUSCOATUM?  No one seems to want to talk about it...
 
Your post was the first I have heard about it, and a websearch came up only with your post to the Dinosauricon.  Darned if I know: I've not heard the name.  It could be that they misspelled the name of the critter.
 
You mentioned there that the "description sounded fishy".  If you could remember (and post) something about the description, maybe we can piece together what they were talking about.
 
                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742      
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796