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RE: New review paper of tyrannosaur paleobiology in Science, with new phylogeny





On Thu, 16 Sep 2010, Jaime Headden wrote:
...

  However, I think it is possible, if not likely, that some taxa can have ontogenetically "juvenile" features while still being adult (paedomorphism). When it comes to generally "juvenile" skeletal and proportionate features in otherwise fundamentally "adult" skeletons that exhibit various other "adult," proportional or ossification trends, one may be permitted the ability to assume or propose a slight paedomorphic trend. Note, for example, that *Xiongguanlong* has an enormously slender and elongate skull, large rounded orbit, and extremely elongate preorbital skull, and large skull relative to its body, but is nonetheless not apparently a juvenile. There should be no constraint that a juvenile morphology should suppress any and all conclusions toward a more mature status, especially given the meagre study so far produced for the taxa presented.

Couldn't some of this just be considered as individual variation?