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Re: Big Dinosaur Prints Found

    Rob said, first quoting me: >(possible of the ichnogenus Kayentapus,
which some writers have said
may have been produced by Dilophosaurus)<

"Until I see a paper matching size of the prints, and the joint positons in
the foot, I'm sceptical of saying that any one animal made these tracks.
There is a lot of fauna in the Kayenta that is poorly known, or unknown from
body fossils at all. So, trying to assign a possible genus to a trackway is
dubious at best, in my mind."

    Quite true, and that's why I said, "...which some writers have said may
have been produced by..."  Generally, a tridactyl theropodan type track is
just that and not very diagnostic.  I suppose that the suggestion that
Kayentapus was of Dilophosaurian origin was because someone thought it to be
the only theropod of the period that had a foot so large, but I would still
ask, 'Is that really so?'  So much of the fossil record is missing or is yet
to be discovered and studied.  I have always personally open-mindedly
questioned the proposed association of Kayentapus with Dilophosaurus.

    Rob also commented, "Personally, I can buy the  pathology argument,
since the occurance of these
traces is fairly rare, and possible trackmakers (read coelophysoids) have a
great degree of stiffness in the ventral plane of flexation, at least in the
anterior portion of the tail. And, look at a human population. There are a
number of people in any town with limps, or other things that would cause an
abnormal trackway. While these people becoming fossilized is not very
likely, one injured/diseased/crippled animal can make many tracks, and these
may be preserved..."

    Indeed.  Furthering the idea of pathological tail drag in a theropod,
one might postulate the following:  It seems the base of the tail might, in
fact, be one rather vulnerable area for another theropod to bite -- even if
the attacker is of the same size or species.  In such a case, the injury
might not be life threatening, but certainly could be severe enough to cause
the tail to subsequently droop or even drag on the ground (ouch?!).

    And as we know, dinosaur tracks and, especially, trackways fortunately
tell us about the life and dynamics of dinosaurs.  So we should not be
surprised to sometimes view ichnological evidence of altered tail carriage
due to injury.

    Ray Stanford