4.  Runty Rex Upsets Dino Doctrine

Scientists reported Thursday that they had identified a fossil, smuggled at one point from China, of a dinosaur that resembles Tyrannosaurus rex but is much smaller. Raptorex, as the specimen has been named, had T. rex's giant head and puny forelimbs, but in young adulthood was just eight feet long and about the weight of a human being. The finding "scrambles the picture of mega-predator evolution and raises the question of whether other jumbo dinosaurs had budget-size versions," according to the Washington Post. That's because the paleontologists have long believed that T. rex developed its bizarre anatomy to compensate for its giant size. "This animal really changes the way we look at all tyrannosaur evolution," according to the lead author of the study, which was published in the journal Science. A private Massachusetts collector bought the 150-pound block of rock that encased the fossil from a private dealer in Tucson, Ariz. The scientists say the fossil is originally from a region of lake beds in northern China, according to the Post.

Read original story in The Washington Post | Thursday, Sept. 17, 2009