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. 2009 Oct 16;326(5951):418-22.
doi: 10.1126/science.1177428. Epub 2009 Sep 17.

Tyrannosaurid Skeletal Design First Evolved at Small Body Size

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Tyrannosaurid Skeletal Design First Evolved at Small Body Size

Paul C Sereno et al. Science. .
Free article


Nearly all of the large-bodied predators (>2.5 tons) on northern continents during the Late Cretaceous were tyrannosaurid dinosaurs. We show that their most conspicuous functional specializations--a proportionately large skull, incisiform premaxillary teeth, expanded jaw-closing musculature, diminutive forelimbs, and hindlimbs with cursorial proportions--were present in a new, small-bodied, basal tyrannosauroid from Lower Cretaceous rocks in northeastern China. These specializations, which were later scaled up in Late Cretaceous tyrannosaurids with body masses approaching 100 times greater, drove the most dominant radiation of macropredators of the Mesozoic.

Comment in

  • Paleontology. Becoming T. rex.
    Clark J. Clark J. Science. 2009 Oct 16;326(5951):373-4. doi: 10.1126/science.1181276. Science. 2009. PMID: 19833946 No abstract available.

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