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Re: Oldest coelurosauria?
In a message dated 7/16/98 6:01:49 AM Eastern Daylight Time, email@example.com writes:
> 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
> the Jurassic and even one from the Late Triassic. There are as example
> Podokesaurus holykensis from the Early Jurassic and Lukousaurus yini from
> Triassic Late/ Early Jurassic period. The therizinosauridae however are
> know from the Cretaceous period so maybe if this is a therizinosaurid from
> the Early Jurassic (Hettangian?) it could by the oldest therizinosaurid
> 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."
"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
"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."