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

Re: Crylophosaurus and Australia

Phil Hore wrote-

> That was kinda my point. was does it have to be an allosaur when we have
more proof, closer to hand of
> there being other types of carnivores, living in the general area, then
Allosaur. I was trying to point out that > we should be looking to places
that were linked to Australia for a better-closer relationship then to
> like laurasia. We should be comparing it, especially as it is older, to
gondwana species like crylophosaurus > whose remains were found almost on
the southern tip (where polar allosaur was found) of australia.

Well, "Allosaurus" "robustus" is no longer thought to be an allosaur.  Azuma
and Currie (2000) found that it resembles Fukuiraptor very closely, which I
agree with.  See http://www.cmnh.org/dinoarch/2002Aug/msg00488.html .  I
understand your point regarding comparing material to taxa that lived
closer, but I don't think it's an issue most of the time, for dinosaurs at
least.  The one exception I can think of is how often people compare teeth
to the Alberta Judith River fauna (tyrannosaurids, Richardoestesia,
Dromaeosaurus, Saurornitholestes, Troodon, Paronychodon).  So we end up with
most of these taxa known woldwide, back to the Late Jurassic.  But that's
because these are the best described teeth that are associated with skeletal
taxa.  Also, I think using geography to help decide phylogeny is problematic
now because we don't have a good idea of what types of dinosaurs were
limited to what areas.  And lots of different kinds of taxa lived in the few
places we have really good records for (eg. Morrison Formation).  I don't
see why other formations wouldn't have as great a variety of taxa if they
were better sampled.

> I have no problem with it being an allosaur, I'm just asking why does it
have to be an allosaur when there
> are better, closer (older) dinosaurs that seem to fit the bill nicely.

Again, how is Cryolophosaurus a "better" relative of "Allosaurus" "robustus"
than Fukuiraptor?  I'm not saying you're wrong, but you need actual
morphological evidence to support your position, not geographical evidence.

> I was justy trying to point out that isolated areas do indeed do exactly
that. There are small populations of
> animals that diversify exactly the way crylophosaurs would have if it was
the only carnivore on gondwana. > Im not of course saying it is
crylophosaurus, Im saying it may be closely akin to it rather then a
> from a whole other continent. Remember, Megalosaurus has also been placed
in queensland, Australia, and > I belive the single bone they had turned out
to be something completely diffrent ( Im really strecthing my
> memory here)

Other Early and Middle Jurassic Gondwanan theropod groups are known.
Coelophysids (Syntarsus), basal tetanurines (Piatnitzkysaurus,
Dandakosaurus?), coelurosaurs? (Ozraptor).  By the Late Jurassic, we have
evidence for ceratosaurs (Elaphrosaurus, Ceratosaurus) and tyrannosauroids?
(Tendaguru teeth) too.  And the only fairly well sampled formations in this
entire span of time in all of Gondwana are the Elliot and Tendaguru.  I'm
sure much more diversity waits undiscovered.  Anyway, Australia simply
wasn't isolated at the time.  It was connected to Antarctica, India, Africa
and South America until the Late Jurassic at least.  So all of the taxa
listed above had the chance to be on Australia by the time it become
I don't think anyone believes the Australian "Megalosaurus" is really
Megalosaurus.  It was common to call any large theropod "Megalosaurus" back
before the 1980's, so a lot of fragmentary bones from all over were referred
to it.

> What I find very interesting is the apparent similarity between north
austrailan dinosaurs to those found in > asia. It seems we just have a lot
more to learn about our little neck of the woods.

The identification of "Allosaurus" "robustus" as a Fukuiraptor relative
would support this idea.  I agree we have a lot more to learn about
Australian dinosaurs.

Mickey Mortimer