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

THERIZINOSAURS FROM THE EARLY JURASSIC



John V Jackson wrote:
<<Yup.  Three wierd discoveries within twelve months, and only George
"Cassandra" Olshevsky's theories predicted them all.  Spooky eh?>>
 
To which Tom Holtz replies with:
<<Very curious statement...>>
 
John replies to that with:
<<Come on Tom - when are you going to give him some credit for his
 predictions?  After all, prediction surely is an important part of that
 fully-agreed-upon unchanging entity you suggest "science" is!>>

I think that Tom was just saying that even though George predicted these
things, he certainly wasn't the only person or first person to predict them.

<<1)  Sinosauropteryx's fluffy stuff>>

George was not the only person to predict this.  If you want to pick a nit,
you can point to Bakker, or perhaps even Huxley or Marsh.
 
<<2)  Caudipteryx (& Protarchaeopteryx)'s feathers>>

Again, the same.
 
<<3)  The early Jurassic "therizino...">>

This was indeed predicted by George, but it is NOT AT ALL inconsistant with
the idea that therizinosaurs are derived coelurosaurs.

Think for a sec, coelurosaurs and carnosaurs are sister taxa.  What is the
first Carnosaur and when did it live?  The answer is Cryolophosaurus and it is
also from the Early Jurassic (probably).  What does that mean?  It means that
coelurosaurs also had to be living in the Early Jurassic too.

There is also the Middle Jurassic coelurosaur skull Proceratosaurs which I
don't see anyone putting up a fuss about.

Eumaniraptorans were around at least in the Middle Jurassic because there are
dromaeosaur teeth from that time.  That puts the origin of the
Maniraptoriformes at a time BEFORE that.

OVIRAPTOR HYPOTHESIS: if therizinosaurs are oviraptors, an Early Jurassic
origin is not at all hard to believe.  Holtz 1994 placed them within
Arctometatarsalia as the outgroup to the Tyrannosaur + Bullatosaur group, and
Sereno 1997 placed them as basal Maniraptora.  Since Maniraptoriformes HAD to
exist at least in the Middle Jurassic, probably sooner, there is no great leap
to say later Early Jurassic.

BULLATOSAURIA HYPOTHESIS: if therizinosaurs are bullatosaurs, an Early
Jurassic origin is not that hard to believe either.  Arctomets had to exist in
the Middle Jurassic at least, and troodonts and ornithomimosaurs had diverged
already by the late Jurassic (Koparion), and some claim now that there were
Morrison Tyrannosaurs too (Stokesosaureus).  So, a Bullatosaur therizinosaur
in the Early Jurassic is not exactly a stretch.

People at first might find it hard to believe that there were a lot of
supposedly "advanced" coelurosaurs running around in the Middle and Early
Jurassic, but realize that they HAD to be simply because a true bird was alive
before the Jurassic was finished.

Because Oviraptors, Dromaeosaurs, and Arctometatarsalians are known from
complete remains in the Late Cretaceous almost exclusively, many people get
the impression that they lived JUST in the Late Cretaceous, but this simply is
not the case.  The Phylogeny INSISTS that they (or their stem-group
"ancestors") had to exist before then, most probably in the Middle and Early
Jurassic.

 <<I'm pleased he was happy.  However I don't expect him or Kevin Padian, when
 referred to in the role of world experts, ever to mention K-BCF>>

What is K-BCF?  Also, I think it best for you to wait a year or two, there
just might be some counter ground-up papers published, perhaps even by some
list members....

 <<. . . which incidentally is adhered to by a respectable section of frequent
contributors
 to this list.>>

Which of course amounts to a while pile of nothing.  No offense to George, but
just because people agree with him doesn't mean he is right :-)  Of course, he
can counter with, just because a lot of people agree that therizinosaurs are
theropods doesn't mean they are :-)

 <<and I'll own up to knowing very nearly nothing about segnosaurs and
absolutely nothing about the early J jaw.>>

I too know next to nothing about this jaw.  It seems to get Nature to western
North America, they throw them in row boats and paddle them across the
Atlantic, then thrown in backpacks and hiked accross the continent then thrown
in the basement of the UW libraries for a few weeks before being put on the
shelves...

Anyway, it is of course possible that this jaw isn't even from a
therizinosaur.  It could belong to a prosauropod or even something like a
heterodontosaur or a stegosaur.  I will need to read the paper (whenever it
shows up...).

Peter Buchholz
Tetanurae@aol.com