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Re: Rigid dinosaurs?

Kent, et al:

It seems that Jack is equating stiff ligaments with ossified tendons.

"Dr Horner and colleagues carried out microscopic analysis of the dinosaur's
vertebrae. They found tissue remnants related to the animal's nuchal
ligament, which provides passive support for the head and neck.

Since the amount found in the vertebrae is proportional to how stiff the
ligament would have been, the researchers determined it would have been very
rigid in their T. rex."

On what extant animal is he basing his analysis that "the amount found in the vertebrae is proportional to how stiff the ligament would have been,"? Does anyone know, or have a guess?

He seems to be ignoring physics in his conclusions.

Kent's example of automotive springs is quite apt and more to the point. An additional note, the larger the vehicle, the larger and stiffer the springs/shocks - therefore, the larger the animal, the larger and the stiffer the [nuchal] ligament.

Allan Edels

From: "Kent A. Stevens" <kent@cs.uoregon.edu>
Reply-To: kent@cs.uoregon.edu
To: dinoboygraphics@aol.com
CC: DML <dinosaur@usc.edu>
Subject: Re: Rigid dinosaurs?
Date: Fri, 17 Feb 2006 08:29:37 -0800

Scott Hartman's "stiff as an ostrich neck" analogy is apt.

Furthermore, to equate ligaments with rigidity only disregards their roles as passive tensile structural elements and in energy storage/ recovery and/or damping.

Race cars and dump trucks (choose your analogy) have stiff springs and shocks for reasons relating to dynamics, not just the static support of the (vehicular) body. Importantly, they aren't rigid, they are stiff.

It would not do for tyrannosaurids to be flopping all over the place as they ran briskly from one carcass to the next in a frenzy of competitive scavenging.

Kent