Tyrannosaur allometry paper in CJES

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

Greetings,

A brief summary of the Currie paper Carroll Festschrift in Canadian Journal
of Earth Sciences.  (Incidentally, Robert Carroll was Phil Currie's graduate
advisor).  This paper represents one of a series of important new
tyrannosaur papers which I've warned is forthcoming for about a year (two
others are mentioned as "in press" in this paper).

Currie, P.J. 2003. Allometric growth in tyrannosaurids (Dinosauria:
Theropoda) from the Upper Cretaceous of North America and Asia.  CJES 40:
651-665

Currie examined over 250 tyrannosaur specimens, taking loads of measurments.
These are shown as bivariate plots.  In general, his main comparisons are
between albertosaurines (Albertosaurus and Gorgosaurus) and tyrannosaurines
(Alioramus, Tarbosaurus, Daspletosaurus, and Tyrannosaurus): the
phylogenetic work for this is in press at Acta Paleontologica Polonica.
Currie considers the medium and small Jordan tyrannosaur material
(Alberto./"Dinotyrannus megagracilis" and Aublysodon/"Stygivenator molnari")
as juveniles of T. rex; and Gorgosaurus lancinator, G. novojilovi,
Shanshanosaurus huoyanshanensis, and Tarbosaurus efremovi as growth stages
in Tarbosaurus bataar.

In general, albertosaurines and tyrannosaurines scale identically.  However,
albertosaurines had slightly shorter, lower skulls, shorter ilia, longer
tibiae, longer metatarsals, and longer toes than tyrannosaurines of the same
body size.  Tyrannosaur forelimbs scale identically except for Tarbosaurus,
which has apomorphically short arms.

Also, Currie has redone Russell's (1970) attempt to determine the
proportions of a 1.5 m long hatchling tyrannosaur, using the new allometric
curves.  Some of the proportions are similar to those proposed by Russell,
but others are considerably different.  I would be interested in seeing an
artist using these data to reconstruct a baby tyrannosaur.  (Currie does
point out the danger in these extrapolations, though.  The reality could be
very different: after all, there are plenty of animals that have "growth
spurts" during ontogeny that violate simply allometric rules).

Cool stuff.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796