[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Tyrannosauroid material from Uzbekistan



I'm curious myself where it's going. Itemirus clearly has characters so far 
exclusive to tyrannosaurids/tyrannosauroids and best allied with them, but some 
coelurosaur braincase characters appear to be highly homoplastic. My abstract 
omits mentioning that it doesn't take too many steps to move Itemirus within 
dromaeosaurids. I also feel that the braincases of Deinonychus and Utahraptor, 
once described, would resolve some uncertainties.

I talked to Dr. Sues and Dr. Averianov at SVP -- there is no doubt that their 
additional materials represent a dromaeosaurid. However, note that the locality 
is a bonebed with many isolated elements jumbled together. I have not seen 
these specimens mentioned in their new paper, so I cannot judge the association 
of these specimens and the holotype braincase.

It's intriguing that it keeps going back and forth between the two extremes of 
non-avian coelurosaurs! Maybe Dale Russell was right.

Tetsuto Miyashita


--- Brad McFeeters <archosauromorph2@hotmail.com> wrote:
> 
> I attended Miyashita's talk at SVP, and he mentioned that he is now less sure 
> of it being a tyrannosauroid than when he wrote the abstract, due to the new 
> material.  
> ----------------------------------------
> > Date: Sun, 20 Nov 2011 23:37:22 -0800
> > From: mickey_mortimer111@msn.com
> > To: dinosaur@usc.edu
> > Subject: RE: Tyrannosauroid material from Uzbekistan
> >
> >
> > And yet Miyashita (2011) found "A redescription of Itemirus medullaris from 
> > the Turonian of Uzbekistan supports the hypothesis that this taxon 
> > represents a relatively derived non-tyrannosaurid tyrannosauroid."  Will be 
> > interesting to see his analysis, in addition to Sues and Averianov's.  Note 
> > Longrich and Currie's analysis only included paravians, so could not 
> > recover a tyrannosauroid position.  No doubt the correct answer is that 
> > Russell and Dong (1994) were right and dromaeosaurids and tyrannosaurids 
> > are sister taxa. ;)
> >
> > Miyashita, 2011. Cranial morphology of the basal tyrannosauroid Itemirus 
> > medullaris and evolution of the brain
umaticity in non-avian coelurosaurs. Journal of Vertebrate Paleontology. SVP 
2011 Abstracts. 159.
> >
> > Mickey Mortimer
> >
> > ----------------------------------------
> > > Date: Mon, 21 Nov 2011 15:11:58 +1100
> > > From: tijawi@gmail.com
> > > To: dinosaur@usc.edu
> > > Subject: Re: Tyrannosauroid material from Uzbekistan
> > >
> > > bh480@scn.org <bh480@scn.org> wrote:
> > >
> > > > Alexander Averianov & Hans-Dieter Sues (2011)
> > > > Skeletal remains of Tyrannosauroidea (Dinosauria: Theropoda) from the
> > > > Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan.
> > > > Cretaceous Research (advance online publication)
> > > > doi:10.1016/j.cretres.2011.11.009
> > > > http://www.sciencedirect.com/science/article/pii/S019566711100187X
> > >
> > >
> > > The paper also features this tantalizing snippet regarding _Itemirus
> > > medullaris_, from the Bissekty Formation:
> > >
> > >
> > > "_Itemirus_ has sometimes been classified as a tyrannosauroid
> > > (e.g., Holtz, 2004), but newly collected material indicates that
> > > it is, in fact, referable to Dromaeosauridae (Sues and Averianov,
> > > in preparation)."
> > >
> > >
> > > It should be noted that _Itemirus_ was found to be a dromaeosaurid (a
> > > velociraptorine, no less) in the phylogenetic analysis of Longrich and
> > > Currie (2009), in their description of _Hesperonychus_. But the
> > > prospect of new _Itemirus_ material is exciting.
> > >
> > >
> > >
> > >
> > >
> > >
> > > Cheers
> > >
> > > Tim
> >
>                           
>