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Re: Claws on deinonychosaurs



Predator traps aside.....Carbon Dioxide burps from lakes have killed humans in Africa and even Yellowstone had a bison kill recently from a gas burp in really cold stratified weather with low wind. There wouldn't be evidence preserved in the fossil record from gassing. It would all be "unsubstantiated speculation". Additionally, falling off a cliff (or down a sand dune :-)) while fighting could cause such a situation with the previously associated remains, scattered by scavengers. Disarticulated, mixed assemblage multiple remains only mean that the animals lived near the same depositional environment at a geologically close time interval. Ripe environment for geologic cartoons eh.

I have several stream valleys on my ranch where I have fossilized bison and elk bones coming out of the valley walls Pleistocene alluvium mixing in the wash with modern domestic/wild mammal bones along side Cretaceous dinosaur fossils coming out of the bedrock. All this in one gully. A close examination of that modern stream bed sediment in 10000 years would be confusing to say the least and laborious to be accurate. One might easily conclude that Cretaceous theropods ate Pleistocene giant bison based on the selective preservation of the fossil enamel teeth (over the Cretaceous bones which break up quickly). Of course the fossilized bison bones would survive well along with the larger numbers of modern bones. Ken is right in that geologic occurrence together doesn't mean living (or grappling) together. This is almost certainly a reason that some dino teeth are not known with the associated owners bones. They are reworked, survivable artifacts. Throw in that rock hammer I lost last year into that stream sediment and some intrepid researcher in the future will have theropods hunting modern humans. (Oops, someone already made a movie about that one!)

Frank (Rooster) Bliss
MS Biostratigraphy
Weston, Wyoming
www.cattleranch.org

On Oct 31, 2005, at 1:37 PM, Ken.Carpenter@dmns.org wrote:

Argh! Somebody please explain to me (not done in the original
description by Maxwell and Ostrom) how multiple predators/scavengers on
a carcass suddenly fall over dead! (and please don't say volcanic ash
because they aren't buried in ash, nor is there evidence for poison gas,
blah, blah). The specimens in question (Deinonychus and Tenontosaurus)
are mostly disarticulated so their association may be incidental). Some
facts, please, rather than unsubstantiated speculation (this is NOT a
criticism directed at Mickey, but my colleagues who make such
statements).


Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology/
Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205

Phone: 303-370-6392
Fax: 303-331-6492
************************************************************
for PDFs of some of my publications, as well as information of the Cedar
Mountain Project:
https://scientists.dmns.org/sites/kencarpenter/default.aspx


-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf
Of Michael Mortimer
Sent: Monday, October 31, 2005 1:21 PM
To: dinosaur@usc.edu
Subject: Re: Claws on deinonychosaurs

Jorge Dichenberg wrote-

Seroiusly, the only reason why Deinonychus etc. were
thought to be predators of large animals was that
sickle claws were interpreted as particulary good
slashing weapon. Now there is little reason to claim
that they were efficent big-game predators. For this,
go to carnosaurs.

Actually, it was because Deinonychus remains were associated with Tenontosaurus skeletons. It's always possible they were scavenging, of course.

Mickey Mortimer