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Re: Eggs,Embyros, and Birds



KARI LYNN BAKER wrote:
> How are scientists able to differentiate between the different egg laying?

-Horner has a book, DINOSAUR BABIES, that covers much of the Egg
Mountain finds.
Miasaur egg clutches are laid in a large pile and then covered by plant
materials, thus separate clutches over time have plant materials and at
least a years' worth of debris separating the layers.  Whether eggs
(from a single clutch) were laid at one pass (like sea turtles) or over
a period of a week (like most song birds) and THEN buried is not known
from the fossils.   Troodons eggs are found TWO at a time along a sort
of trail for about 10-15 feet.  I think it was Betty White working near
Egg Mountain that suggested a dual ovipositor explanation for Troodon's
odd egg distribution.  I don't know enough about egg-laying biology but
it does seem a rather unusual method.

I don't know in what arrangement sauropod eggs are found but I think
it's supposed to be a sort of spiralled eggmound (that might be
hadrosaurs I'm remembering).

In the case of the 'nesting' ovaraptor the eggs were touching the dead
animal, indicating a same-layer horizon.  Same with the cases where
juveniles of one species are found in nests of another species.  With
eggshells from the nest actually STUCK to the faces of the dead animal,
it's pretty obvious also they were in the same horizon.

-Betty Cunningham