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Re: Origin of feathers



I wrote:
<<How then, would *Oviraptor* have covered the laterally lying eggs? If 
contact occured between dino and egg as seen within the nest, then did 
this mean the eggs were exposed, or was the contact accidental? If 
exposed, the eggs would have fried within their shells. Not very 
productive to survival of the species, when one lays extra eggs just to 
boil them. Now, if not exposed, can we think of a bird that sits on a 
nest of buried eggs? The cassowary builds a mound, and occasionally sits 
on it, but this mound has the eggs far below the surface, and as far as 
we can tell, any pre-sandslide covering the eggs would ahve had would 
have been thin.>>

Jeff Hecht wrote:
<I must admit I'm rather confused about some of the details. Various 
people who I expect to know far more than I do have said that the eggs 
were or were not buried in sand in the nest before they were covered by 
the landslide (or whatever event fossilized the nest). I don't know 
who's right.>

  The likeliest possibility is that the eggs were ringed in sand, but 
directly underneath was bare. Sitting on the nest suggests direct 
incubation, not mound incubating; the arm thing could have been a fluke, 
but it is only a part of the riddle. That fact that Ovi was _sitting_ 
there in the first place cannot be laid at the feet of accidental or 
postmortem position, and predation, I'm sure, has been discarded.

  Feathers in a bird-like animal is too possible, and even if the arms 
weren't feathered, again the likeliest possibility is that feathers or 
feather-like or even protofeather or rachi _were_ present, for no living 
animal that sits its eggs or young in this fashion (atop them) is 
bare-skinned. To create a sufficient cool area or even warmth in cold 
times, feathers would be the most ideal, and evolution does generally 
follow this course. What is most likely to be used in a given situation 
is usually there, or a sufficient analogy is present.

<One suggestion has been that multiple animals laid the eggs, and one 
stayed with the nest, brooding, guarding or whatever.>

  Ostriches and rheas (and perhaps a few others, but these come to mind 
most readily). Male incubates and broods and guards and rears all young, 
while female gallivants, mates with other males, and lays the eggs in 
the first guy's nest, so he will eventually be brooding up to five 
male's eggs.

  But the structure of the nest suggests one animal laid the eggs 
(uniform, paired, circular, double-decker), or cared for the eggs to the 
degree that the nest sitter was either one of a pair, and/or the layer 
of said nest, being female, which is my opinion on that matter. There is 
an altogether ordered and artificial sense to the nest, and to my 
knowledge a female is the only sex that does this for the eggs, either 
paired or single.

<The suggestion that Oviraptor might have been laying eggs is 
interesting. Can you tell anything about the possibility from the 
position of the skeleton and the eggs?>

  It was a possibility only, and I personally do not think it too 
likely, considering the Currie & Dong (1993) find of the Iren Debasu 
nests with one oviraptor laying the eggs in a pattern, feet in the 
hollow center (the incubator from Ukhaa Tolgod has the feet outside the 
center, so this was after the laying) and actually (not preserved, to my 
knowledge) laying an egg, when WHAM! A fossil digger finds her. Sexual 
identity in a dino confirmed?

Jaime A. Headden

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