OVIRAPTOROSAURIA! Part One [Overview]

["Jaime A. Headden" <qilongia@yahoo.com>]

WE INTERRUPT THIS REGULARLY-SCHEDULED DINOSAUR LIST DISCUSSION TO
BRING YOU THE FOLLOWING:

  A recent study done by amateur paleontologist Jaime A. Headden on
the case of the Oviraptorosauria has produced some unexpected results,
which will be explained shortly.

  Just recently, a strange animal has come to a brighter
paleontological and public light, with incredible new finds in Canada
and America, Mongolia, and China, made in just the last 8 years, and
has since relegated what was once considered fact into what may prove
falsehood, and theory into what may prove fact.

  It begins with the American-Mongolian Expeditions into the Gobi
desert undertaken by paleontologist, geologist, ornithologist, and
mammologists, almost 70 years after the famed Central Asiatic
Expeditions led by infamous Roy Chapman Andrews, and the less famous
paleontologist, Walter Granger.

  New discoveries included an embryonic oviraptor in an egg shell that
has previously been called *Protoceratops*, a skeleton lying over a
nest of such eggs (another was found in China, a year earlier), and
the skulls and skeletons of many more, plus many more untended nests.

  Such discoveries have shown that the eggs were laid, tended and
nested by oviraptors, not protoceratopsids, as Osborn (1924a) had
first theorized. The embryo proved the eggs were oviraptors.

  The position of the nesting oviraptor has startling implications:
first, oviraptors sat upon their nests in a brooding, avian posture;
second, oviraptorids would seem to wrap their long, gorilla
proportioned arms around the perimeter of the nest, suggesting an
avian mantle-type posture; third, oviraptorids were feathered.

  How to prove these? Jaime Headden has given some interesting
arguments to prove an old theory, as well as offering the disclaimers
to these implications.

  First, oviraptorids could have been transported to the site---seeing
the sedimentation, which is non-depositional, meaning the animal was
not moved by any force of nature (wind, water, etc.) and was static in
position at time of death/burial; the animal could have been feeding
on the eggs, showing a feasting position taken over the nest, but none
of the preserved eggs show predation, and the hindlimbs are tucked
perfectly at the sides, suggesting careful arrangement, as well as the
positioning of the arms. How likely is it that oviraptors could have
been cannibalistic, as the argument might propose? It is likely, but
again, the careful position of the body is too deliberate, and not
likely for an egg-eating parent.

  Second, the position of the arms may be accidental, moved by some
natural force as the weight of the burying sand, and as this may well
be true, the symmetry of both arms to the midline of the skeleton is
almost perfect, and crushing weight from above, forcing the pectoral
girdle (the shoulders) into the ground and splaying the arms out,
would still require the arms to be positioned sideways in a symmetry,
otherwise the arms might have been crushed forward, or underneath the
fossil.

  Third, presuming the position of the arms are not accidental but
deliberate, the oviraptor seems to "wrap" the arms about the lateral
edge of the nest, in a back-swept "wing" position taken in some birds
(ostriches, some passerines) that would assume shading the eggs, and
this would seem very likely, but this mantling position is usually
only taken after the eggs have hatching, as when it rains, to protect
the chicks. 
This, though, could not be facilitated by bare arms, and so some form
of integument would be required to shade them, and the first
possibility is feathers. Dinosaurs with feathers? If so, it would
finalize the debate once and for all whether birds are dinosaurs, or
that birds and dinosaurs developed parallel and that their most recent
common ansector had the ability to produce feathers, still, assuming
birds and dinosaurs are closer to each other (in the same taxon,
usually assumed to be Dinosauria) than to any other animal. An
argument goes in favor of the arms-as-mantle, in the form of
ostriches, who do shade their eggs when it is very hot, and the Gobi
environment would seem to be as hot as it is today, assuming the
oviraptor would shade the eggs to prevent them from heating up,
effectively boiling them. Feathers would be the easiest form of
integument to produce with ancestors like *Sinosauropteryx* with
"protofeathers" that resemble nothing but feather shafts, or rachi.

  Altogether, the nest and arm woudl indicate a very avian situation
for oviraptors.

  This post continues...

  Jaime A. Headden
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