Witmer and Horner on Tyrannosaurus rex
From Michael Ryan's (CMN) blog, Palaeoblog, Larry Witmer (University of Ohio's Associate Professor of Anatomy) and Jack Horner (Montana State University's Museum of the Rockies' Curator of Vertebrate Paleontology) have a series of presentations at this year's American Association for the Advancement of Science meeting in St. Louis, Missouri (always in the USA):
Larry Witmer's talk:
T. rex appears to have had sensory systems that were "even more heightened than we thought," said Ohio University paleontologist Lawrence Witmer. That's based on CT scans of fossilized dinosaur skulls that can indicate the size of areas devoted to particular tasks. Such an analysis indicates that T. rex had "an inner ear structure consistent with a dynamic lifestyle involving rapid tracking movements of the eyes and head," Witmer said. Based on brain size, the senses of smell, sight, hearing and balance were also relatively well-developed.Indeed, because you see, Tyrannosaurus needed those tracking and jerky head capability to keep an eye on all the other tyrannosaurs that wanted to steal the animal that keeled over for no explicit reason, but makes a good scavenging target.
Witmer joined with Jack Horner to discussion general motion:
T. rex was not particularly agile — even though it's portrayed that way in "Jurassic Park" and other dinosaur movies. based on the biomechanical evidence, Witmer and Horner agreed that T. rex couldn't jump or run in the sense of having both feet off the ground at once. "We have an animal that looks like it should be agile, but isn't. ... I don't think T. rex could dance," Horner said.It's actually nice to see some neurological data to add to this discussion on tyrannosaur speed, but this doesn't conclude anything that Hutchinson and Hutchinson & Garcia haven't said already: that Tyrannosaurus did not have the muscle mass in its legs required to move it faster than, say a quick walk for maybe a slow jog, and certainly seems to show it couldn't acheive a suspension phase in its stride. But I gather Horner's introduction into this is that predators need to run, so it was a scavenger. Perhaps, maybe, but then, no one is assessing speed in the prey to date, either. Thus arguments about the utility of speed in prey capture are meaningless as long as Tyrannosaurus is in a vacuum.
Carrano, M. T. & J. R. Hutchinson. 2002. Pelvic and hindlimb musculature of Tyrannosaurus rex (Dinosauria: Theropoda). Journal of Morphology 253:207-228. (free pdf available from J. Morph.)
Hutchinson, J. R. & M. Garcia. 2002. Tyrannosaurus was not a fast runner. Nature 415:1018–1021. (subscription based fulltext and pdf of paper)