*Giganotosaurus* running 50 km/h

["David Marjanovic" <david.marjanovic@gmx.at>]

This just in from http://www.paleo.pan.pl/acta/acta46-2.htm:

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Blanco, R.E. & Mazzetta, G.V. 2001. A new approach to evaluate the cursorial
ability of the giant theropod Giganotosaurus carolinii. - Acta
Palaeontologica Polonica 46, 2, 193-202.

The cursorial capability of the South American giant theropod Giganotosaurus
carolinii should have been quite limited taking into account the strength
indicator of its femur (approximately 7 GPa-1) as well as the risk of
experiencing grave or even lethal injuries involved in the falling of this
multitonne animal on a run. However, even at low speeds a fall would have
caused serious injuries. Thus, in accordance to the approach developed in
this study, the maximum speed of Giganotosaurus should be not that which
will implicate corporal lesions with minimum probability of lethalness.
Instead, its maximum speed should be that which would permit the recovery of
body equilibrium as each step is taken. Taking into consideration this
approach, an indicator of stability is defined for bipedal, cursorial
animals. This indicator is determined by the relationship between the time
available for the movement of hip joint during the retraction of a hindlimb
and the time needed to move the opposite hindlimb by an angle (in function
of the speed) of sufficient magnitude as to facilitate the recovery of body
equilibrium. This indicator was used to estimate the maximum speed of
locomotion of Giganotosaurus (about 14 m s-1) at which, from a kinematic
point of view, the danger of falling does not exist.
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14 m/s are 50.4 km/h. :-o This implies tyrannosaurs, with more cursorial
limb proportions, should have been even faster.