Re: Pterosaur embryo found in egg

["T. Michael Keesey" <mightyodinn@yahoo.com>]

--- K and T Dykes <ktdykes@arcor.de> wrote:
> Hi Ben,
> 
> thanks for posting that one.  And thanks are also due to the mind-blowing
> fossils from the Lower K of China.

Thanks for dying, little animals! :)

Seriously, though, this is one exciting dicovery!

> <<The embryonic skeleton, which is exquisitely preserved in its egg, is
> associated with eggshell fragments, wing membranes and skin imprints.>>
> 
> That seems to suggest at least one pterosaur laid eggs, the shells of which
> could fragment; ie. an egg a with hard shell as known from crocs, non-birdy
> dinos and birdies.  That sounds like a very archosaurian kind of thing to
> do.

Or at least archosauromorphan. The major hypotheses of pterosaur origins place
them either in the immediate outgroup to _Dinosauromorpha_ ("The Ornithodiran
Hypothesis") or outside _Archosauria_ sensu stricto (the most exclusive clade
containing crocodylians and avians), but still within _Archosauromorpha_ (the
most inclusive clade containing archosaurs but not lepidosaurs), possibly as
part of _Prolacertiformes_ ("The Prolacertiform Hypothesis").

Under the Ornithodiran Hypothesis, any feature seen in both crocodylians and
dinosaurs would be expected to be present in at least basal pterosauromorphs.
If, on the other hand, pterosaurs are non-archosaurian archosauromorphs, any
feature seen in both crocodylians and dinosaurs still *might* be present in
basal pterosauromorphs. Thus, eggs like those of crocodylians and dinosaurs are
compatible with either hypothesis, and do nothing to resolve the relationships 
further.

=====
=====> T. Michael Keesey <http://dino.lm.com/contact>
=====> The Dinosauricon <http://dinosauricon.com>
=====> Instant Messenger <Ric Blayze>
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