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RE: _Microraptor zhaoianus_



Incidentally, _Microraptor_ (or at least part of it...) is well known to the
list.  The tail of "Archaeoraptor" is from the counterslab to the specimen
here; in other words, this is the rest of the "dromaeosaur" (which I am not
convinced it is...) to which part of "Archaeoraptor" was made.  It looks as
if the stuff they have (and in particular the hindquarters) all goes
together: I'd still feel more secure if I knew that the specimen had been
CAT scanned.

_Microraptor_ is a little guy, and is morphologically very close to the
common ancestor of Avialae, Dromaeosauridae, and Troodontidae.  It has
features from all three, and I'd like to see the specimen up close and
personal to get it into my new matrix; I'm really not at all secure that it
would fall out closer to _Deinonychus_ or _Velociraptor_ or _Dromaeosaurus_
than to, say, _Troodon_ or _Rahonavis_ or _Archaeopteryx_.

Incidentally, some of the interesting features:
*The fuzz near its butt... er, pelvis look like the longer elements on the
arms of (among others) _Beipiaosaurus_ and _Sinornithosaurus_.  However, in
this specimen these structures are interpreted as having a central rachis.
*The metatarsal I and pedal digit I are very distally placed, and the
penultimate phalanx of each of the toes is elongate: Xu et al. interpret
this as indicating a climbing habit.
*The pes is interpreted as being arctometatarsalian: wish it were preserved
with the anterior face in view so we could see for certain.
*The teeth are waisted, and the denition is heterodont.

Incidentally, the trivial nomen _zhaoianus_ honors Zhao Xijin (of
_Sinraptor_ & _Monolophosaurus_ fame), who apparently introduced Xu Xing to
the field of vertebrate paleontology.  (Always a good thing to see teachers
getting honored!)

Pet peeve alert: I've already seen news items calling this a "missing link".
AARRRGGHH!!  If you have a specimen in hand, it isn't missing!

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796


> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> MKIRKALDY@aol.com
> Sent: Wednesday, December 06, 2000 3:18 PM
> To: dinosaur@usc.edu
> Subject: _Microraptor zhaoianus_
>
>
> Tomorrow's Nature contains a paper on "The smallest known
> non-avian theropod dinosaur."  Xing Xu, Zhonghe Zhou and Xiaolin
> Wang report on _Microraptor zhaoianus_ as "the first mature
> non-avian dinosaur to be found that is smaller than
> _Archaeopteryx_, and it eliminates the size disparity between the
> earliest birds and their closest non-avian theropod relatives."
> There are "large patches of integuments...preserved in situ
> around the skeleton."  "Some pedal features of _Microraptor_ are
> consistent with an arboreal habit."
>
> Mary
> mkirkaldy@aol.com
>