Re: Chimeras (was Re: Protoavis & Drepanosauridae (sensu Renesto, 1999)

[Dinogeorge@aol.com]

In a message dated 4/30/01 12:32:48 PM EST, twilliams_alpha@hotmail.com 
writes:

<< The lack of available material for comparison (if correctly associated, 
and 
 irrespective of its proposed avian identity, _Protoavis_ appears to be a 
 unique taxon) and the fact that many elements are poorly preserved, conspire 
 to add a degree of uncertainty to the identifications attached to many of 
 the elements. >>

In all the cases of chimeras you cited, the remains were truly scanty and/or 
were not found in association. With Protoavis there are lots of different 
bones, found in association--enough that one could expect, if there were more 
than one kind of animal mixed in, to find a few "extras." Of course, it is 
always >possible< that by some extraordinary chance none of the bones of any 
one individual survived that survived in any of the others. The greater the 
number of chimerized individuals, however, the smaller the chance that this 
could happen. So if you're going to assert that Protoavis has been put 
together out of an archosaur, a bird, a prolacertiform, and a 
megalancosaurid, for example, I think you're going >way< out of your way to 
debunk the material. I think it's more likely that the tidy little ground-up 
scenario that the cladists have put together is wrong, than that Protoavis is 
that kind of chimera.