Re: Triassic dino tracks in this week's Science

[Dann Pigdon <dannj@alphalink.com.au>]

"Emma C. Rainforth" wrote:
> 
> Olsen did.
> 
> >THIS reference maybe. But what of the papers refered to? Did you go back
> >to the original description in 1964?

Excellant. Then this makes you case even stronger. Of course a truly
dedicated scientist would have flown to the other side of the world and
actually gone down the coal mine... :)

I'm not suggesting these tracks WERE made by a theropod, but rather that
the possibility is there. It seems the major reason why they are
'suggested' to have 'possibly' been pseudosuchian is because the
existance of large Carnian carnivores goes against the authors'
theories:

"Although the comment of Thulborn (2)
addresses a number of paleontological issues
in (1), his only point salient to the
conclusions of our paper is his extraordinary
claim that very large theropod dinosaurs
were already present in the Carnian..."

Pseudosuchian tracks CAN be ill-preserved in a way that makes them look
theropodian (I may have invented that word). However claiming that the
Queensland prints ARE pseudosuchian relies on negative evidence - namely
that certain features (like two other toes) may not have been preserved.
As a scientist, I tend to concentrate on what IS preserved, not what may
not have been. Then again, perhaps that's just me.

When Jurassic labyrinthodont remains were found in Queensland, the
world's labyrinthodont experts tried desperately to re-date the deposits
to conform to accepted theories. When other Jurassic specimens turned up
elsewhere, it was accepted. Then, when Cretaceous labyrinthodont remains
were found, skepticism and out-right disbelief once again reared their
ugly heads.

Now we have two ulnae that resemble those of protoceratopids, from Early
Cretaceous deposits in Australia (115 MYA). Have they been
misidentified? Or do our theories on ceratopid evolution and
biogeography need to be revised?

Sure, isolated single finds MAY be misidentified. Then again, they might
just be the tip of the iceburg. In time, other large Carnian theropod
prints may be found elsewhere (if they haven't been already). Or they
may not. We'll just have to wait and see...

-- 
________________________________________________________________

Dann Pigdon                   Australian Dinosaurs:
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://www.alphalink.com.au/~dannj/
________________________________________________________________