New papers: T. rex, Saturnalia

["bh480@scn.org" <bh480@scn.org>]

From: Ben Creisler bh480@scn.org

Don't recall if these papers have been mentioned here. Just in case they
haven't:

Henderson and Snively (2003). Tyrannosaurus en pointe: allometry minimized
rotational inertia of large carnivorous dinosaurs [Biology Letter] :
Proceedings: Biological Sciences (advance online publication)
 Abstract: Theropod dinosaurs attained the largest body sizes among
terrestrial predators, and were also unique in being exclusively bipedal.
With only two limbs for propulsion and balance, theropods would have been
greatly constrained in their locomotor performance at large body size.
Using three-dimensional restorations of the axial bodies and limbs of 12
theropod dinosaurs, and determining their rotational inertias (RIs) about a
vertical axis, we show that these animals expressed a pattern of phyletic
size increase that minimized the increase in RI associated with increases
in body size. By contrast, the RI of six quadrupedal, carnivorous
archosaurs exhibited changes in body proportions that were closer to those
predicted by isometry. Correlations of low RI with high agility in lizards
suggest that large theropods, with low relative RI, could engage in
activities requiring higher agility than would be possible with isometric
scaling.

Langer, M.C. 2003.The pelvic and hind limb anatomy of the
stem-sauropodomorph Saturnalia tupiniquim (Late Triassic, Brazil) PaleoBios
23(2):, September 15, 2003
Three partial skeletons allow a nearly complete description of the sacrum,
pelvic girdle, and hind limb of the stemsauropodomorph Saturnalia
tupiniquim, from the Late Triassic Santa Maria Formation, South Brazil. The
new morphological data gathered from these specimens considerably improves
our knowledge of the anatomy of basal dinosaurs, providing the basis for a
reassessment of various morphological transformations that occurred in the
early evolution of these reptiles. These include an increase in the number
of sacral vertebrae, the development of a brevis fossa, the perforation of
the acetabulum, the inturning of the femoral head, as well as various
modifications in the insertion of the iliofemoral musculature and the
tibio-tarsal articulation. In addition, the reconstruction of the pelvic
musculature of Saturnalia, along with a study of its locomotion pattern,
indicates that the hind limb of early dinosaurs did not perform only a
fore-and-aft stiff rotation in the parasagittal plane, but that lateral and
medial movements of the leg were also present and important. 



--------------------------------------------------------------------
mail2web - Check your email from the web at
http://mail2web.com/ .