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FW: Feathered dinos



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> Date: Sun=2C 8 Nov 2009 14:05:30 +0100
> From: nekarius@hotmail.com
> To: DINOSAUR@usc.edu
> CC: dinosaur@usc.edu
> Subject: RE: Feathered dinos
>

Don't correlate feathers with fur. See below.
=20
=20
>
> I'd like to have your opinion about filamentous integuments in dinosaurs =
since I got this conversation with my teacher in palaeontology about feathe=
red dinosaurs and the preservation of feathers and protofeathers. He told m=
e interesting things I was not aware of.
>
> I was convinced that some compsognathids such as 'Compsognathus' and 'Jur=
avenator' were devoid of filamentous integuments. The latter are not visibl=
e on the specimens while both compsognathids are very well preserved in fin=
e-grained sediment (I think there are both lithographic limestone). I thoug=
ht that some Compsognathidae did not possess these filamentous structure=2C=
 contrary to 'Sinocalliopteryx' and 'Sinornithosaurus' were they are visibl=
e. But my teacher told me that the feathers of some specimens of Archaeopte=
ryx are not preserved at all=2C though there were fossilised exactly in the=
 same lithographic limestone as the other specimens. Therefore=2C this coul=
d exactly be the same with 'Compsognathus' (both the German and the French =
fossils) and 'Juravenator' and the filamentous integuments. All compsognath=
ids=2C and therefore all coelurosaurs=2C possessed filamentous integuments=
=2C according to him. Such quite complex structure=2C like hairs in mammals=
=2C can not disappear in a clade. It can be reduced or just be present in s=
ome part of the body=2C but not disappear.
>
> Besides=2C according to him=2C the discovery of a basal ornithischian (an=
 heterodontosaurid) with the same filamentous integuments as the ones disco=
vered in coelurosaurs therefore demonstrate that filamentous structure is a=
 condition shared by ALL dinosaurs=2C even sauropodomorphs=2C marginocephal=
s and thyreophores. However=2C giant dinosaurs such as sauropods=2C many ce=
ratopsians=2C ornithopods and theropods would have had only minimal "hair" =
as we can see in our living elephants and hippopotamus. That's why we would=
 find a scaly skin in some of them when we've got the impression of the ski=
n...

=20
I'd be careful here since feathers and hair are radically different in thei=
r structure. The loss of hair in mammals because of size does not necessari=
ly=20
correlate well with the same supposed loss in fuzzy dinos. In fact=2C the l=
arger=20
the bird the larger the feathers and the greater the covering. Even small b=
irds
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 en=
tirely
draped in feathers. Maybe someday eh??
=20
=20

> The second part of the conversation was on the correlation between the pr=
esence of these filamentous structures and homoeothermy. What can we say ab=
out this? If there really exists a correlation between the presence of fuzz=
 and homoeothermy=2C what my teacher would assume=2C than all dinosaurs wer=
e homoeothermic animals. According to him=2C homoeothermy was already prese=
nt in pterosaurs=2C first because they were flying animals (again=2C he wou=
ld assume that all flying vertebrate are homoeotherms)=2C second because we=
 also have the evidence of filamentous structures in some of them (but not =
all).
>
> So=2C I'd really like to get your opinion about these points because I'm =
absolutely not knowledgeable about homoeothermy and the evolution of filame=
ntous integuments.
>
> Thanks in advance and sorry for the mistakes in English=2C
>
> C.H.
> http://spinosauridae.fr.gd/
>
>> Date: Sat=2C 7 Nov 2009 21:02:50 -0500
>> From: tholtz@umd.edu
>> To: soylentgreenistrex@yahoo.com
>> CC: dinosaur@usc.edu
>> Subject: Feathered dinos (was RE: New BBC series research-fine feathered=
 dinos)
>>
>> B tH wrote:
>>> While N.A. has had several feathered dinos
>>> discovered=2C it has seemed that the Mongolian-Chinese
>>> fossil record is 'richer' in these animals (going by
>>> the various news outlets.)
>>> Is that just chance?
>>> Could the environments have been different enough
>>> to spur feathers in what is today's Orient?
>>
>> Let's not mistake "feathered dinosaurs" for "dinosaur fossils with
>> feathers preserved".
>>
>> North America has many fossils of feathered dinosaurs (avialians=2C
>> dromaeosaurids=2C troodontids=2C oviraptorosaurs=2C alvarezsaurids=2C
>> ornithomimosaurs=2C tyrannosauroids)=2C just none preserved with feather=
s on
>> them. The Asian fossils are preserved in very fine-grained sediments
>> which preserve the carbonized feathers (and also which preferentially
>> preserve small-bodied animals). The North american fossils are typically
>> preserved in river deposits=2C which do not preserve such details.
>>
>> --
>> Thomas R. Holtz=2C Jr.
>> Email: tholtz@umd.edu Phone: 301-405-4084
>> Office: Centreville 1216
>> Senior Lecturer=2C Vertebrate Paleontology
>> Dept. of Geology=2C University of Maryland
>> http://www.geol.umd.edu/~tholtz/
>> Fax: 301-314-9661
>>
>> Faculty Director=2C Earth=2C Life & Time Program=2C College Park Scholar=
s
>> http://www.geol.umd.edu/~jmerck/eltsite/
>> Faculty Director=2C Science & Global Change Program=2C College Park Scho=
lars
>> http://www.geol.umd.edu/sgc
>> Fax: 301-314-9843
>>
>> Mailing Address: Thomas R. Holtz=2C Jr.
>> Department of Geology
>> Building 237=2C Room 1117
>> University of Maryland
>> College Park=2C MD 20742 USA
>>
>>
>
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