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Sinosauropteryx



Several questions were proposed earlier today regarding Sinosauropteryx.
I can try to answer then, but I have NOT seen the SVP abstract (Geist,
et al). However, J. Ruben did prepare a dissection of the tail of a sea
snake which is flattened dorso/ventrally. The color photos that I saw
contain fibrous material, which are most likely collagen.
   The presence of collagen in this tissue is no suprise. The basic origin
 is mesodermal and collagen is the support tissue involved. There are
differences in the density of the fibers in the 2 tissues, but that is
probably not significant. There is, in fact, a simple way to resolve this.
All that need be done is to measure the fiber diameter in the Sinosauropteryx
material. Keratin and Collagen differ in the fiber diameter, and this can
probably be done with the material now available. The lab in Nanjing is
familiar with the thin section techniques and have both TEM and SEM scopes
on the campus.I suggested to Chen Pei-ji that preciesly this be done.
   While we were in China Larry Martin also came up with the observation
that Sinosauropteryx might have been semi-acquatic. Perhaps presuing prey
into shallow water etc. The flattened tail, or a rod-like tail with a
frill might have been an aid to moving. Like one might use an oar to move
a small boat. Could be, who knows?
   I don't know exactly what all Geist et al, have actually seen in terms
of material. Photos as we all know can be misleading. I'd say go to his
talk and find out.
   I don't have an easy answer for why integument (or any other tissue)
 fossilizes in any one particular way. Certainly the posture of the beast is
important and each of the Sinosaurpoteryx seems to reside on its side.

    In my experience all extant birds, and I've looked at a lot of them, have
 feathers that with a tiny bit of careful looking can be identified as
 such. Eye lashes and facial bristles are very hair-like, but always have
 barbs at the base. Filoplumes, on the other hand, are extemely abundant on
 most birds. For a great proportion of their length, they lack barbs. But
 they are always present on the tips. There are other examples of specialized
 feathers--usually involved in displays--that lack barbs over some of
 their length.
     The plumage of young penguins (despite their appearance in photo)
  consists of very dense down feathers. Same for the neck of the Ostrich.
 This stuff feels like felt or soft material, but is feathers and feathers
 only.Ralph Miller is exactly right "eyeballing a glossy magazine image cannot
compare with viewing the  actual feathers under magnification."
    BTW, many of the feathers in the plumage of adult penguins have fused barbs
which give then a scale-like appearance. But they too are feathers (made of
the feather protein, not scale-sized molecules).

                           Cheers,
                                     Alan