Re: Wrong Reconstructions

["Habib, Michael" <MHabib@Chatham.edu>]

On Jan 25, 2011, at 4:34 PM, Jaime Headden wrote:

> The real issue is that aside from the "ebff"s, "feathers" in all fossils are 
> non-plumulaceous, lacking apparent barbs, and nothing similar to "feathers" 
> in the conventional (modern) sense.

This does seem to be the case for the most part, but I've been wondering 
recently about how literally we can take this observation.  My general question 
(and I'm keen to see what others here think) is this: given an animal *with* 
modern-grade, plumulaceous feathers, what are the chances that it would 
preserve with that feather structure clearly apparent?  Might we just be seeing 
minor traces of much heavier feathering in many species?

Consider:
- The first dromeosaurids discovered with feather impressions seemed to show 
relatively non-barbous feather structures, but subsequent finds of quill knobs 
in Velociraptor and the feathering in Microraptorines might suggest that more 
"modern" grade feathers were present in a wider range of taxa, and just don't 
always show up clearly.

- In some specimens a range of feather types is preserved, which provides 
confidence that those apparently lacking barbs were indeed downy in that 
individual.  However, often the feather impressions are somewhat uniform, 
possibly suggesting that we are only seeing trace elements of feather 
structure.  There are Confuciusornis specimens that look merely "fuzzy" (pardon 
my intense use of technical jargon there...), for example - we know from other 
specimens that, in fact, this taxon possessed contour feathers.  One wonders 
how often this happens, given that most taxa are not represented by hundreds of 
specimens in the manner of Confuciusornis.

Just food for thought.

--Mike


>         

Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181