From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
On Behalf Of Hammer
Sent: Tuesday, August 05, 2008 10:15 PM
To: dinosaur@usc.edu
Subject: nana vs. juvenile rex
Well, the way Nanotyrannus was animated on tonight's JFC, they made
it appear as a different species from T. rex very strikingly. The
juvenile rex looked like an adult merely "shrank down" -
looked to me as though the legs were not in proportion to
what they should have been in a juvenile and the head
especially was not right ... right?
Precisely. They just took their T. rex model and shrank the
dimensions.
To paraphrase Samuel L. Jackson: "Allometry, motherf**er. Do You
Speak It?"
Yes, a T. rex the same mass as a "Nanotyrannus" would look remarkably
like... Nanotyrannus. And this is true regardless of whether they
are sister
taxa, the same species, or whatever: Currie has shown that limb
allometry in
the different tyrannosaurid subgroups are fairly consistent.
So - anyway - what do think?
Ummm... Better luck next episode?
Seriously, this one had less fact checking than the first. The
graphics
consistently read "Nanotyrannosaurus" rather than "Nanotyrannus";
the dates
for the Cretaceous were off by 10 Myr (they gave it as 135-55
Ma!?!); the
graphics for the teeth were wrong (esp. missing the deep tyrant
roots); the
"septic bite" argument would hold for all serrated theropod teeth,
and not
uniquely for T. rex; and while the graphics model was good their
animation
step cycle (especially for a run) was way off (it appeared that the
footfalls were further from the midline than while walking, when
instead
footfalls should be in line (that is, closer to the midline than the
legs
are while standing)).
Thomas R. Holtz, Jr.
Email: tholtz@umd.edu Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661
Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA