Agonized death throes probable cause of open-mouthed, head-back pose of many di...( Berkeley -- The peculiar pose of many ...)

Agonized death throes probable cause of open-mouthed, head-back pose of many dino fossils

Berkeley -- The peculiar pose of many fossilized dinosaurs, with wide-open mouth, head thrown back and recurved tail, likely results from the agonized death throes typical of brain damage and asphyxiation, according to two paleontologists.

A classic example of the posture, which has puzzled paleontologists for ages, is the 150 million-year-old Archaeopteryx, the first-known example of a feathered dinosaur and the proposed link between dinosaurs and present-day birds.

"Virtually all articulated specimens of Archaeopteryx are in this posture, exhibiting a classic pose of head thrown back, jaws open, back and tail reflexed backward and limbs contracted," said Kevin Padian, professor of integrative biology and curator in the Museum of Paleontology at the University of California, Berkeley. He and Cynthia Marshall Faux of the Museum of the Rockies published their findings in the March issue of the quarterly journal Paleobiology, which appeared this week.

Dinosaurs and their relatives, ranging from the flying pterosaurs to Tyrannosaurus rex, as well as many early mammals, have been found exhibiting this posture. The explanation usually given by paleontologists is that the dinosaurs died in water and the currents drifted the bones into that position, or that rigor mortis or drying muscles, tendons and ligaments contorted the limbs.

"I'm reading this in the literature and thinking, "This doesn't make any sense to me as a veterinarian,'" said lead author Faux (pronounced fox), a veterinarian-turned-paleontologist who also is a curatorial affiliate with Yale University's Peabody Museum. "Paleontologists aren't around sick and dying animals the way a veterinarian is, where you see this posture all the time in disease processes, in strychnine cases, in animals hit by a car or in some sort of extremis."

Faux and Padian argue in Paleobiology that the dinosaurs died in this posture as a result of damage to the central nervous sy
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Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
8-Jun-2007

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