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Re: Oldest coelurosauria?



In a message dated 7/16/98 6:01:49 AM Eastern Daylight Time, fb@nrc.nl writes:
<SNIP>
> 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.  The therizinosauridae however are
only 
> know from the Cretaceous period so maybe if this is a therizinosaurid from 
> the Early Jurassic (Hettangian?) it could by the oldest therizinosaurid
known 
> but surtenly not the oldest coelurosaurid.
>  

>From the paper:
"The Lower Lufeng Formation was initially thought to have been formed 
in the Late Triassic but it is now widely accepted to be of Early Jurassic 
origin on the basis of the invertebrate (such as costracod, pelecypod 
and gastropod) and vertebrate (for example, prosauropod and the 
tritylodontid Bienotherium) fossils it contains."
<SNIP>
"Previously, the oldest definitive records of Coelurosauria were 
Ornitholestes and Coelurus from the Late Jurassic Morrison Formation 
and Compsognathus from the Late Jurassic of Germany and France. 
The oldest of these specimens are from beds correlated with the 
Kimmeridgean marine stage. Isolated teeth tentatively identified as 
dromaeosaurid have been found in Middle Jurassic deposits. The Late 
Triassic Protoavis texensis may also belong to this group, but questions 
have been raised about the association and interpretation of the material. 
The new specimen is therefore the oldest fossil definitively referable to 
Coelurosauria, extending the record of this group back by roughly 30 
million years."
<SNIP>
"The presence of a non-avian coelurosaurian in the Early Jurassic 
indicates that by the Late Jurassic the major clades of this group 
must have already diverged, well before Archaeopteryx appears in 
the fossil record."

Mary
mkirkaldy@aol.com