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On the idea that dinosaur?/bird feathers and pterosaur fur are
homologous and that all dinosaurs had the geentic potential for sporting
feathers at least part of thier lives, I'm thinking about Greg Paul's
paper in Dinosaur Eggs and Babies about insulation in hatchlings.8
Small babies exposed to the elements have a major problem
with temeperature control, being so small. If I am not mistaken,
MOST endothermic animals huddle up with thier offpring at night
to keep them warm. Considering the size of parent
dinosaurs, sitting on thier babies to keep them warm is not a viable option.
The suggestion was that feather insulation was present in these hatchlings
(perhaps to be lost at a later stage in life). How do baby ectotherms keep
However, as I noted in previous postings, this would only work if
dinosaurs (or at least the babies) were endothermic. Feathers and fur
insulate, which is useful if you are generating your heat metabolically
and don't want to loose what you are producing. However, if you are an
ectotherm trying to get heat from the environment, the heat would be
absorbed by the feathers and not reach the body.
It there even the possibility that early feathers might have
included some kind of blood vessel network? If so, they may have been
used to increase the heating surface area, a good thing for an ectotherm.
However, it is my impression that feathers are compositionally simple
structures (although they can be pretty complex structually), and that such a
set up is unlikely. If so, I think that the possesion of a covering like
feathers or fur is a good indication of endothermy.
In either casse, I will be VERY interested to see what a careful
examination of the structures on this Chinese compsognathid reveals.
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