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Re: Psittacosaurus adult found with 34 juveniles




Evan Robinson wrote:
> 
> >Perhaps not by sitting ON them - but a bristled tail wrapped around
> >them? I'm thinking of how wolves and foxes use their tails as 'blankets'
> >during cold weather.
> 
> Interesting idea. A large female cobra wraps her body around her eggs and
> assists in egg incubation by flexing her muscles and vibrating. Of course
> the Cobra?s eggs have leathery shells.! ?
> 
> How about those Early Cretaceous Hypsilophodontids down your way in
> southeastern Australia? Do workers still think that a lack of LAG lines
> indicates an elevated metabolic rate? (They were in the Antarctic circle at
> the time). How do you suppose that they kept their eggs warm enough to
> hatch? Is there any eggshell associated with them?

No actual egg shell, although many of the deposits represent stream
channels, so perhaps egg shell didn't preserve in those condition.
However numerous hypsie embryonic bones are known (both in Victoria and
the opal fields of South Australia), so they definitely bred in these
colder areas.

As for elevated metabolic rates; given the lack of LAGs and the large
eyes, it seems as if they were adapted to toughing out the dark winter
months. The theropod Timimus from the same area has quite pronouced
LAGs. I like to think of hypsies as being like the polar-nesting bird
equivalent of the Cretaceous (think flightless geese). If many theropods
were unable to handle the most severe of winter conditions, then
sticking around at those times would have been a great predator
avoidance strategy for the hypsies.

Perhaps live-birth for some polar hypsies was not out of the question?

-- 
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Dann Pigdon
GIS / Archaeologist         http://www.geocities.com/dannsdinosaurs
Melbourne, Australia        http://heretichides.ravencommunity.net/
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