Pterosaur embryo and soft-shelled eggs

[Jeff Hecht <jeff@jeffhecht.com>]

At 5:03 PM -0700 6/9/04, Jaime A. Headden wrote:
>   Actually, most of the Lower Cretaceous Liaoning/Liaoxi/Nei Mongol
> fossils are preserved much as in the microraptor specimens, in that bone
> is crushed, diameters distorted, longitudinal and sometimes transverse and
> diagonal cracks are present, shapes deformed, and skulls tending to be
> "shattered" in nature with some disarticulation (the holotypes of
> *Sapeornis* and *Microraptor zhaoianus* are disarticulated, the former
> more than the latter). There are very few "complete" skulls, and pelvises
> are almost always disarticulated to some degree, limbs broken and
> shattered or digits distorted.

WHich raises an interesting point about the pterosaur embryo just 
reported from the Yixian deposits. Like most of the other fossils 
from those deposits, it's squashed very flat, with some bones 
apparently disarticulated as a result. (I haven't seen the fossil, 
just a PDF of the Nature paper.) That suggests to Dave Unwin (whom I 
interviewed for a New Scientist story to appear in this week's issue) 
that pterosaur eggs were soft-shelled, so they could be squashed flat 
without breaking. He thought hard-shelled eggs would be shattered.

So... have dinosaur eggs been found in the Yixian deposits? If so, 
are they shattered of flattened?

--
Jeff Hecht,    science and technology writer
Boston Correspondent, New Scientist magazine
Contributing Editor        Laser Focus World
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