A critical ligamentous mechanism in the evolution of avian flight

Article Abstract:

A study is conducted to show that the force balance system of the shoulder of birds evolved from a primarily muscular mechanism to one in which the acrocoracohumeral ligament has a critical role. Features of the shoulder of Mesozoic birds and closely related theropod dinosaurs indicate that the evolution of flight preceded the acquisition of the ligament-based force balance system and that some basal birds are intermediate in shoulder morphology.

Physiological aspects, Birds, Bird flight, Ligaments

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Beyond the bones

Article Abstract:

A case study is provided on the way to embrace the uncertainty in reconstruction of the locomotion of extinct animals through the use of computer animation and simulation, taking Tyrannosaurus rex as an example. Paleontologists have two main options when confirming redundant in an articulate chain of bones that include to set arbitrary constraints on the system to reduce the number of possibilities and invoke simple geometric rules.

Extinct animals, Tyrannosaurus rex

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