[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Feathered dinos



Michael Erickson was truncated:

 Von Huene (1901) reported extensive dermal armor in the holotype of
 _Compso= gnathus longipes_. These "osteoderms" were later
 re-interpreted as eggs by = Griffiths (1993). However=2C not a single
 one of these "eggs" are to found = within the body cavity of the
 animal=2C which is very odd indeed. Then ther= e's the specimen of
 _Sinosauropteryx_ described by Chen et al. (1998) that = DOES show
 two un-laid eggs in the oviduct. These eggs are much larger than =
 the supposed "eggs" of-_Compsognathus_=2C and far less numerous. This
 casts= considerable doubt on the identification of the objects in the
 _Compsognat= hus longipes_ holotype as eggs. It seems to me that [v]on
 Huene may have righ= t all along. This is bolstered by Peyer's (2006)
 discovery of scales on the= caudal vertebrae of the _Compsognathus_
 "corallestris" holotype (which ARE= scales=3B that they are preserved
 on the bones themselves does not have be= aring on their
 identification as such=2C for scales are preserved on the bo= nes
 themselves in the manus of Sternberg's "trachodon" mummy as well).
 =20

Shouting "ARE" doesn't make it so. Those strange bumps are _only_ preserved on the vertebrae and look as if they're part of the vertebrae, not something that lies on top of them. AFAIK the same kind of thing has been found on bird bones from Messel.

Hasn't the "dermal armor" been identified as an artefact of the grainy matrix or something?

> So what I'm saying is that two specimens of _Compsognathus_=2C one with pro= > bable dermal armor=2C another with definite caudal scales=2C and without a = > single tiny trace of feathers between them is suggestive to me that feather= > s 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 cours= > e=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 suspiciously = > 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?

In both specimens of *Compsognathus*, no skin is preserved at all whatsoever (except for those "scales" on each caudal vertebra). They're just naked bone. This is absence of evidence, not evidence of absence.

*Juravenator* has scales (very different ones from the bumpy caudals of *C.*), but 1) on most of the body the skin is missing, and 2) it's probably not a compsognathid.

And yes, of all the integument, most *Archaeopteryx* specimens preserve only the wing and tail feathers, no contour feathers, downs, stage III feathers or whatever.