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Cannibal _Coelophysis_

Jonathan Wagner wrote:

Note that even finding one specimen articulated within another does
not PROVE ingestion (as some point out regarding the infamous
"cannibal" ceolophysis... but don't ask me, I've never seen the thing).<

To which Jerry D. Harris responded:
This assertion came from an observation -- I don't know who is supposed to have originally made it -- that one can see the ribs from _both_ the left and right sides of the adult _Coelophysis_ overlying the supposedly-ingested juvenile -- this would imply that the juvenile isn't inside the adult's peritoneal cavity, but that the adult is _on top_ the juvenile.<
Colbert, 1989, originally described this, and I think restates it in 1990 in Dino. Systematics. There are several problems I have with the "cannibal" hypothesis, the first of which HP Harris brings up. The juvenile isn't inside the rib cage. But, for the sake of argument, lets say it was originally ingested, and the bones later somehow slipped out. The volume of bones is greater than the volume of the presumed stomach. These bones could not have physically fit inside the digestive tract of _Coelophysis_. Point three...judging only from the casts I have seen, there appears to be no acid etching on the supposed "victim". Point four...on the casts of this specimen I have examined, all show the destinctive outline of other bones covered by sediment (particularly, a femur below the ribcage). If you have ever seen a well-prepped Ghost Ranch block, you know how unlikely it is for there to be no other animals exposed on the surface. Either the other animals were never prepped out, or, as has been told to me by other parties, Chinle sediments were actually placed on top of the other specimens, to give a better view of this animal. There is no evidence for cannibalism in _Coelophysis_.
And with this, I leave for the weekend to go to Phoenix, and watch the Sharks and Coyotes play. Go Sharks!

Student of Geology
Northern Arizona University
P.O. Box 20840
Flagstaff, Az. 86011
AIM: TarryAGoat
"A _Coelophysis_ with feathers?"

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