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Dinosaur speeds: question



I understand that medium-sized theropod tracks from the Glen Rose
Formation in Texas Texas have been interpreted to represent an animal
something like a young _Acrocanthosaurus_ individual running at about 25
mph (see Gregory S. Paul's out-of-print 1988 _Predatory Dinosaurs of the
World_, figure 5-2, p. 130).  Yet in figure 6.3 on pp. 138-139 of the
same book, Paul depicts a trackway of an early Jurassic 10 kg dinosaur
from Arizona, either a theropod or an ornithopod, which exhibits stride
lengths approaching 4 meters, leading Paul to arrive at a calculated
speed of "about 40 mph."  Paul points out that Welles (1970) and
Thulborn (1982) attribute the tracks to dinosaurs with absurdly short
feet (1/10 the leg length as opposed to the expected 1/4 leg length
figure), thus skewing speed calculations.

I am completely willing to accept the 40 mph figure, but I am curious
why I have seen no other source since 1988 publish a comparable
calculated top speed for dinosaur tracks.  Have scientists other than
Bakker come around to the conclusion that these tracks do indeed show
evidence for a dinosaur running 40 mph, or does Paul's interpretation
still represent the minority opinion among those who have studied the
tracks and calculated the speed of the trackmaker?  I continue to see 25
mph given as the top speed according to trackway evidence.  Having said
this, I understand full well that top speeds are very rarely recorded in
animal trackways today, so neither figure necessarily represents the top
speed attainable by a (non-avian) dinosaur; the trackmakers could well
have run faster, particularly on dry ground.
--
Ralph W. Miller III  <gbabcock@best.com>