Re: DINOSAUR digest 675

[paleo@ix.netcom.com (Glen J. Kuban )]

In response to Roger Stephensen's question about dinosaur tail marks, 
and whether they may be less rare than originally thought.

In short, dinosaur tail marks ARE quite rare.  I have done extensive 
work on Cretaceous dinsoaur tracks (especially in texas, where I have 
examined and mapped literally hundreds of trackways).  I have seen only 
ONE marking I would describe as an almost certain tail drag, and only a 
few others I would classify as possible tail marks.  Most trackways 
show no sign of a tail mark.  The same goes for Cretaceous sites I have 
examined inthe Western U.S. and the largest triassic tracksite known 
(the Culpepper VA site).  The early Jurassic redbeds of New England 
seem to show tail marks somewhat more frequently, but even there the 
vast majority of trackways show no tail marks.  From all this I would 
conclude that the majority of dinosaurs routinely held their tail off 
the ground while moving, although occassional tail marks and drags are 
known and not surprising, since it would be expected that a few wounded 
animals or broken tails would exist, or that a flexible tail would 
occassionally contact the ground.  The rarity of tail drags can no 
longer be reasonably attribute to "floating tails" since even where 
tracks cross mudcracks and other evidence that little if any water was 
present, tail marks are just as rare.  
James Farlow of Indiana/Purdue Univ at Fort Wayne has worked with me on 
several sites and done extensive track work on his own, and might be 
able to add his own assessment of ttail mark frequency, but I believe 
in general he would concur with my remarks.  Martin Lockley of course 
would be another person to poll since he has done extensive work on 
tracksites in the Western U.S.