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RE: Feathered dinos



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Well=2C it seems that some messages are truncated=2C as the latter I sent (=
and that I received without any truncation...). Don't know why (virus?). So=
rry about that. Anyway...
=A0
> Michael Erickson wrote:
> So what I'm saying is that two specimens of _Compsognathus_=2C one with p=
robable dermal armor=2C another with definite caudal scales=2C and without =
a single tiny trace of feathers between them is suggestive to me that feath=
ers were either greatly reduced in distribution on the body of this taxon=
=2C or were altogether absent (the former may be more likely). Then=2C of c=
ourse=2C there's Juravenator=2C which has preserved on the matrix very tiny=
=2C soft=2C and fine scales around the hind limbs and tail=2C but suspiciou=
sly no feathers. Again=2C the scales are very small=2C fine=2C and soft=2C =
only very slightly less so than feathers. Why were they preserved=2C while =
the feathers=2C if they were present=2C were not?
=A0
Actually=2C I believe we do not expect to find feathers in Compsognathidae =
because they are the most basal clade of theropods with filamentous structu=
res (if we consider them to be more basal than Tyrannosauroidea). These str=
ucture are "proto-proto-feathers". Having say that=2C as David Marjanovic s=
aid=2C no skin is preserved at all in both 'Compsognathus' specimens and we=
 can therefore assume they could have had filamentous integuments as 'Sinor=
nithosaurus' possessed.
=A0
=A0
> Dale Mcinnes wrote:
> Don't correlate feathers with fur.
> I'd be careful here since feathers and hair are radically different in th=
eir structure. The loss of hair in mammals because of size does not necessa=
rily correlate well with the same supposed loss in fuzzy dinos. In fact=A0 =
the larger the bird the larger the feathers and the greater the covering. E=
ven small birds may possess large feathers. There is no discernable loss of=
 these structure s in extant birds because of the increase in size. I could=
 even see sauropods entirely draped in feathers. Maybe someday eh??
=A0
Well=2C I correlate hairs with the filamentous integumentary structures fou=
nd in some basal coelurosaurs which I can also qualified as "poil" (=3Dhair=
) in French=2C even the structure is different from the 'true' hair in mamm=
als. That's why I used the word "fuzz" when referring to the deep appendage=
s found in many coelurosaurs ('Beipiaosaurus'=2C 'Sinornithosaurus'=2C 'Dil=
ong'=2C etc.) and 'Tianyulong'. Indeed=2C the structure of these filamentou=
s appendages found in dinosaurs are different with those found in mammals (=
and pterosaurs=2C I believe)=2C I totally agree=2C but their utility is exa=
ctly the same: thermal insulation. Therefore=2C I think it is likely to ima=
gine that these filamentous structures were almost invisible in very big di=
nosaurs=2C as it is the case in mammals.
=A0
Second=2C I do not believe at all that feathers were present in other non-t=
heropod clades=2C even the latter could have had filamentous structures in =
some part of their body=2C along with the scaly skin. No need to say what=
=2C it goes without saying.
=A0
=A0
Christophe Hendrickx
http://spinosauridae.fr.gd/
                                         =20
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