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Re: drowned dinosaurs



 I'd like to add a new spin on the drowned dinosaur body position thats been
discussed recently. At our Pachyrhinosaurus bonebed I noticed that most of
the complete or relatively complete ribs are from the right side of the
body. Left side ribs are either missing or busted up. I first noticed this
in 1988 and during our very productive 1989 field season kept a close eye on
ribs as we uncovered them in the field. The good right side and bad left
side ribs phenomenon was very real. I hypothesized that: Assuming the
pachyrhinosaurs died in a regional flooding event, the drowned carcasses
would assume a preferred orientation, not necessarily head upstream or
downstream, but with one side facing up (skyward) more than the other side.
While skin, muscle and bone is more or less symmetrical in the body, the
internal organs are not. So, a dead and rotting (and bloated) pachyrhinosaur
with an off center stomach filled with gas would float with the lighter side
up (the side with the gas filled stomach). The dead pachyrhinosaurs floated
left side up and were then dumped along the shoreline or crevasse splay-type
region. Carnosaurs large and small scavenged the carcasses (we have teeth
and toothmarked bone to confirm this) from the left side, thus accounting
for the left side ribs being busted up. Subsequent weathering further broke
up the uppermost ribs. The right side ribs, cradled in the mud escaped the
immediate attentions of carnivores and being cradled in the mud were
afforded a small degree of protection. I've mentioned this pachyrhinosaur
situation to some taphonomists and they mentioned having seen a preferred
orientation of one side facing up in drowned megamammals in Africa. How I
wish I could have been in Quebec in 1983 and leap from Caribou carcass to
carcass noting which side was up! Has anyone seen or heard of anything
similar in extant populations? I'm willing to bet that casrcasses of animals
will float in predictable and regular positions, possibly based on internal
organ arrangment. I seem to recall that human drowning victims will adopt
different positions in the water depending on the particualar circumstances
at time of death. Any forensic pathologists out there?

 I'm sending this communication on what I think is a somewhat screwed up
software package/server, so sorry for any resultant problems.

 "HADROSAURS CHEW, TYRANNOSAURUS WRECKS"

  

          


























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































 
 Darren Tanke, Technician I, Dinosaur Research Program, Royal Tyrrell Museum
of Palaeontology, Box 7500, Drumheller, AB, Canada T0J 0Y0. (403) 823-7707;
(403) 823-7131 (fax); e-mail= dtanke@dns.magtech.ab.ca
 Paleo Interests: fossil identification and preparation, ceratopsians, Upper
Cretaceous vertebrate faunas of North America and East Asia, paleopathology;
senior editor on annotated bibliography of extinct/extant vertebrate dental
pathology, osteopathy and related topics (9,200 entries as of Jan. 10, 1996).