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Sinornithosaurus and Negative Evidence
It's an open question if this new feathered dinosaur, which shows barbules,
is either a juvenile specimen of Sinornithosaurus or a new genus.
Earlier this year Xu, X., Z.-h. Z. & R.O. Prum found no signs of barbules in
"Branched integumental structures in Sinornithosaurus and the origin of
feathers" (Nature 410: 200-204).
So if the new feathered dinosaur can be proven to be a juvenile
Sinornithosaurus adults must have had them too.
But in any case it's time again to recall Dr. No (negative evidence please!
formerly known as Dr. Thomas R. Holtz, Jr. (sorry, couldn't resist)). As he
always reminds us that absence of evidence is not evidence of absence.
In this case the missing barbules are used as an argument against the
feathery structure of the integument of Sinornithosaurus. But perfect
fossilization is very, very rare. So when integumentary structures are found
these may (or may not) tell us only part of the whole story. So there's (for
now) no proof for or against barbules in Sinornithosaurus.
Regarding positive evidence: In September 1999 there was an ABC article about
Sinornithosaurus which quoted Larry Martin as saying that he wanted to see
fossils of lizards and other critters from Liaoning in case they show similar
"feathers"--proving that the halos are not external integument. This would be
positive evidence proofing that Sinornithosaurus had no barbules, not even
any kind of feathers. But up to now no feathered frogs etc. have been found
Heinz Peter Bredow
BTW: Thanks to Luis Rey for his early warning of things to come (the
feathered dinosaur) in "My own SVP Experience (Long)" in December 2000. He
> Letâs say that after fifteen years of dreaming and speculating (and many
> times having withstood abuse, disbelief and scorn), finally all my
> dreams came true at the stroke of an opening drawer!
I waited and yes, it was worth the waiting.