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RE: The tail of Jeholornis...




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Jaime A. Headden
Sent: Thursday, July 25, 2002 5:56 PM
To: dinosaur@usc.edu
Cc: tholtz@geol.umd.edu
Subject: Re: The tail of Jeholornis...

Tom Holtz(tholtz@geol.umd.edu) wrote:

<Although the abstract and paper call it dromaeosaurid-like, this is
probably simply an ornithologists-eye-view: it is actually a more
generalized eumaniraptoran tail (not terribly surprising, actually), more
like a troodontid or (perhaps, when we know the whole animal) _Rahonavis_,
or an elongated (in terms of number of vertebrae) _Archaeopteryx_. The
prezygapophyses (cranial zygapophyses, for those who like  the Nomina
Anatomica Avium) and chevrons (haemal arches) ARE elongate relative to
those of typical Cretaceous birds and _Archaeopteryx_, but they are NOT
the hyperelongate forms of dromaeosaurids (and in fact the zygs aren't
terribly long next to those on the distal caudals of, for example,
ornithomimids).>

  Indeed, however the chevrons do appear to have some
overlapping/interlocking morphology. It is also curious that, despite the
figure in the paper (having now read it) half the trees (from the suppl.
info) result in a sister-group relationship between *Jeholornis* and
*Rahonavis*, and variations in the tree are otherwise restricted to
neornithean ingroups. Curious stuff. Will want to compare in more
detail...<<

I take it if I said, can we wait for the paper before the long discussions,
would be out of line? :)

<More stuff still to come out of Liaoning, though, and not all of it
eumaniraptoran!>

  Good! I hope some of it is ornithischian, at least. I would, however,
like to see what a diverse non-theropodan fauna is present and am
presently getting ready to look at various suchians, lizards, snakes, etc.
that may be present.... If anyone could help me with the lower Jehol
Group: Yixian, Jiufotang, and Tuchengzi Formations, I would very much
appreciate it.<<

I've seen some pictures from Ralph Molnar that he took when he visited
Liaoning. Perhaps a new 'type' of psittacosaur, at least (I think) 4
articulated sauropod cervicals (large animal), a Caudipteryx that would
stand 4 feet at the hips (or was it total height?), more birds, more
theropods. The major emphasis is on the theropods and birds, but there are
(as you said), other interesting animals.

  Cheers,


Tracy L. Ford
P. O. Box 1171
Poway Ca  92074