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Re: Oldest Coelurosaurian Found



At 10:34 PM 7/15/98 EDT, Mary Kirkaldy wrote:
>The July 16, 1998 issue of Nature announces a new therizinosaur (no 
>name given) (Nature 394, 234-235) "The Oldest Coelurosaurian" - Xijin 
>Zhao, Xing Xu.

>"This specimen (V11579, held at the Institute of Vertebrate 
>Paleontology and Paleoanthropology, Beijing), consisting of most 
>of the left dentary and part of the splenial, was collected from 
>the bottom of dull, purplish beds of the Lower Lufeng Formation of 
>Eshan County, Yunnan."
><SNIP>

>"The new specimen is therefore the oldest fossil definitively referable 
>to Coelurosauria, extending the record of this group back by roughly 
>30 million years."

Bloody hell... I just WROTE the section on oldest coelurosaurs in the new
theropod phylogeny paper!

In the as-yet unpublished new phylogeny of mine, the oldest coelurosaurs
documented are Proceratosaurus bradleyi (Bathonian) and Gasosaurus
constructus (?Bathonian-?Callovian).  The Lower Lufeng is Early Jurassic,
and thus predates these two Middle Jurassic forms.

Fred Bervoets wrote:
>Coelurosauridae are of my knowledge know through out the Mesozoic period in
much casses this are nomia dubia but there are also descriptions of some
specimens of coelurosauria from the Jurassic and even one from the Late
Triassic. There are as example  Podokesaurus holykensis from the Early
Jurassic and Lukousaurus yini from the Triassic Late/ Early Jurassic period.

Neither of these forms have been convincingly shown to be coelurosaurs:
Podekesaurus might be a coelophysoid ceratosaur, and Lukosaurus may not even
be a dinosaur, much less a theropod, much less a coelurosaur.

(Incidentally, as there is no taxon "Coelurosaurus", there is no
"Coelurosauridae".  The proper term is "Coelurosauria".)


I have GOT to see this new specimen.  Who knows: a very early
therizinosauroid may indeed prove Dinogeorge correct, and show that all the
coelurosaurian features of therizinosauroids are convergences.
Alternatively, it might be primitive enough that some of the coelurosaurian
features lost in Cretaceous therizinosauroids may not have been yet transformed.

This is what makes paleo fun! 

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661