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Re: DINOSAUR digest 3468 (Oviraptors=Parrots?)



Jorge Dichenberg (jorgedich@yahoo.com) wrote:

<Animal the size of Oviraptor could break any eggshell without special
adaptations.>

  An animal the size of *Oviraptor* had an eight inch skull, not a behemoth
contraption of steel and iron. This was bone, made from thin struts with large
apses between them, and while it had attachments for large muscle and the space
to accomodate them, the function of the jaws in a biomechanical sense is far
from explained.

<Nice, so predator theory is falling.>

  Who said this? I was describing a semi-narrative about the way the evidence
was arrived at and the reasons others doubted previous data. Since Norell et
al. have not described any data that costradicts Barsbold, they have used other
data to suggest an alternate, or combined, mode.

<Many birds are vegetarian as adults but feed animal food to nestlings.>

  We have no evidence oviraptorids ate plants.

<For example, many finches and sparrows are seed-eaters, but bring insects to
nest. Asian hornbills are fruit-eaters, but succesfully hunt small animals to
feed chicks.>

  Hornbills also successfuly feed on tiny mammals and lizards to feed
themselves, and will even use them to profer food to potential mates.

<If oviraptorids could manipulate food with their hands, it would compensate
for akinetic skull.>

  How manipulative would hands be if they only faced in one direction and could
only extend and fold in one way? Given also that oviraptorids have a small
skull on a long and slender neck with more vertebrae than the typical theropod,
one can reasonably suggest the hands were unneccesary for rotating eggs or
lizards or such. But they seem ideal, rather, for grasping prey. And by prey, I
mean animals much larger than your average lizard. Also don't forget that
oviraptorids probably had tongues which, like in parrots, could have been
manipulative.

<Every seed must fall to the ground to germinate. So, unless there was a niche
of seed-eating pterosaurs, oviraptorids could feed on ground or with limited
climbing.>

  How many seed plants available in these formations? Enough to sustain or
supplement the diet of all oviraptorids within the area? Don't forget that
there were plenty of lizards and mammals that may have been seed-eaters,
including the seemingly well-adapted multituberculates, which possess the
overhanging shearing incisors and broad, multicupsed and low-crowned molars of
seed-eaters.

<I always thought it is not phylogeny-related, but common to long-billed birds
with short tongues. No need for throwing food if you have beak so short as
parrot or oviraptorid.>

  It is possible that for some birds, the long snout may have evolved for the
purpose of drinking and feeding on tiny prey. Note that hydrostatic pressure
allows the bird to dip only the tip of the beak into the water in passing to
drink, as the pressure of the water drops forces it to adhere the the beak's
surface as the bird opens its jaws, bringing the water into the mouth.
Oviraptorids are way to large to make use of this, but I wouldn't put it past
them to use suction and lapping like most animals (including large birds!)
their size.

<But now seed-eating seems more plausible.>

  But what seed-eating adaptations and what seeds are available enough to drive
the evolution of a skull so derived from any typical, long-snouted and toothy
ancestor?

  Cheers,

Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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