Paul G writes (12.04):

Welsh and Chinese (and other nationality) dragons do have a common origin,
according to someone I heard a few months ago on the radio. I can't
remember this person's name, but I gathered he was some sort of freelance
London intellectual. It was on Resonance FM, and the programme was mainly
about Frank Zappa. His explanation was that the dragon came about as a
result of early attempts to explain, and then to represent in pictorial
form, comets. Fire-breathing, tailed, tearing across the sky: it sounds
good enough to me.

And L. Alberts writes (8.04):

Have you considered that dragons, as they are often depicted, show a remarkable resemblence to various types of dinosaurs? Now, say you have never heard about dinosaurs, know nothing of their prehistoric existance... and one day you find the skull of this dinosaur in the rocks, what would you make of it?

My best guess is that it will somehow be interwoven into stories of times long forgotten...

That this large and untouchable creature made the earth tremble, and the mountain spit fire.etc. etc. etc.

Anyways, hope it helps, was actually looking for how often the batmobile caught a flat... :)

L writes (4.04):

Not a precise anwser, but it might interest you. Dragons in China (so I
read somewhere) are spirits and can live in the air, the sea, the earth etc.
So when, for example, you build a house on a hill you should build it in
such a way as not to disturb the dragon that lives under it. They are
connected - or identified - with the energies beneath the earth, which the
Celts called ley-lines (unless this term was just invented last century by
that bloke who wrote a book about them). Before the birth of King Arthur,
Uther Pendragon (I think it was him) had a dream about a white dragon and a
red one fighting underground: a disturbance in the energies...
I can't think of any reason for European (dragon myths were everywhere, not
just in Wales) and Chinese mythology being linked at that period of history:
unless it is that dragons actually exist and we just can't see them any
more.