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

Re: New JVP dinos



Dinogeorge wrote

> The third number of this year's JVP arrived here today and there are two
new
> dinosaurs in it. First is Nothronychus mckinleyi Kirkland & Wolfe, 2001,
> which we've all known about, and it is no longer a nomen nudum. And second
is
> Eshanosaurus deguchiianus Xu, Zhao & Clark, 2001, which is represented by
> that therizinosauroid mandible from the Early Jurassic of China.

Could someone (with a copy of the 3rd JVP issue 2001) give more details on
the new Eshanosaurus deguchiianus ?

While initially proposed as an early therizinosauroid, more recent comments
indicated that it probably was a "prosauropod", similar to Lufengosaurus (a
contemporary?). I understand from Dinogeorge's posting that it is again
mentioned as a therizinosauroid.

Is it now unquestionably identified as a therizinosaur ?
Is the proposed early Jurassic age correct ?
Or does the JVP paper only contain a description of the fossils, without
definitely establishing its phylogenetic position ?

If Eshanosaurus is indeed an early Jurassic therizinosauroid, then this
would mean that;

1. Eshanosaurus pushes back therizinosaur origins by some 60 million years
(until now, Beipiaosaurus is the oldest definite therizinosaur, some 125
MYA)
2. Eshanosaurus is not only the earliest known therizinosaur, but also the
earliest known maniraptoran (beating Archaeopteryx and also other less
well-known late Jurassic maniraptorans).
3. It becomes increasingly probable that all advanced maniraptoran clades
had evolved soon after the rise of the dinosaurs (during the late Triassic),
as several workers (including Chatterjee) have suggested.

Some technical comments would be welcome.


Regards,

Gunter Van Acker

GunterVanAcker.mesozoic@pi.be
or
Gunter.VanAcker@Electrabel.be