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Re: Something else complete different: Triassic Crurotarsi vs Ornithodira in latest Science
My article for New Scientist is now up on line, and includes plots of the
morphospaces of Triassic archosaurs as well as photos of their skulls. See
It's good work that tells us some very interesting things about archosaur
evolution, and leaves us to ponder what the crurotarsans did wrong at the end
of the Triassic, and why two fundamentally similar lineages persisted so long
in the same environments.
At 5:54 PM -0400 9/11/08, Thomas R. Holtz, Jr. wrote:
>Brusatte, S.L., M.J. Benton, M. Ruta, G.T. Lloyd. 2008. Superiority,
>Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs.
>The rise and diversification of the dinosaurs in the Late Triassic, from 230
>to 200 million years ago, is a classic example of an evolutionary radiation
>with supposed competitive replacement. A comparison of evolutionary rates
>and morphological disparity of basal dinosaurs and their chief
>"competitors," the crurotarsan archosaurs, shows that dinosaurs exhibited
>lower disparity and an indistinguishable rate of character evolution. The
>radiation of Triassic archosaurs as a whole is characterized by declining
>evolutionary rates and increasing disparity, suggesting a decoupling of
>character evolution from body plan variety. The results strongly suggest
>that historical contingency, rather than prolonged competition or general
>"superiority," was the primary factor in the rise of dinosaurs.
Jeff Hecht, science & technology writer
525 Auburn St., Auburndale, MA 02466 USA