Gallery: 6 Surprising New Tyrannosaurs Discovered This Year
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For more than a century, *Tyrannosaurus rex* has been the King of Dinosaurs, the carnivorous symbol of an entire age in the history of life on Earth. That image no longer holds. Over the last decade, a series of discoveries have radically expanded our knowledge of the *Tyrannosauroidea*. *T. rex* now seems less like the taxonomical superfamily's patriarch than an odd cousin. "*T. rex* is so iconic. Everybody has that image of it," said American Museum of Natural History paleontologist Stephen Brusatte. "T. rex in many ways were very unusual tyrannosaurs. They're not the norm for the group now." As described in a September 17 *Science* article co-authored by Brusatte, tyrannosaurs came in a wide range of sizes, shapes and habits over their 100 million year history. Most were small and overshadowed by other, larger predators. Only at the end did *T. rex* and its Asian counterpart, *Tarbosaurus*, cast their tyrant shadows. "A lot of this work is new. It's as contemporary as paleontology gets," said Brusatte. "We wrote this review to pay homage to these discoveries, and to change perception of tyrannosaurs." To meet some of the other notable members of *T. rex*'s family, click on. *Image: [Rich Middleditch](http://www.flickr.com/photos/middric/4534382714/), Flickr.*
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Perhaps no dinosaur contrasts more starkly with traditional expectations than *Kileskus*, a genus featuring tyrannosaurs the size of small dogs, with long, low skulls. "It's very primitive and a bit bizarre," said Brusatte. Along with the similarly-shaped but larger *Guanlong* (pictured) and *Proceratosaurus*, paleontologists put these genuses in their own family, Proceratosauridae. *Images:* Guanlong/Wikimedia Commons.
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Not every other tyrannosaur was tiny, or fit a linear narrative of smaller animals evolving into larger. *Sinotyrannus* predated *T. rex* by 40 million years, but was nearly as big. "This is the only example that we know of tyrannosaurs being really big early in their history," said Brusatte. "As far as we know, it was a total outlier." *Image: Brusatte's tyrannosaur superfamily tree./Science.*
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Meet *Dilong* wasn't just small, but probably feathered. Filament-like impressions in its fossils suggest plumage — something that many dinosaurs, not just proto-birds, possessed. Some of the materials that give pigmentation to living feathers may still be present in those fossils. According to Brusatte, we might eventually know their colors. *Image: Dennis Finnin, American Museum of Natural History*
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Living about 15 million years before *T. rex* in what is now China, *Bistahieversor* was a transitional creature. "*T. rex* probably evolved from a similar animal. This is the oldest species we know that's really large. It seems to be present just at the beginning of when tyrannosaurs got huge," said Brusatte. "It was right on the cusp." *Image: David Baccadutre, New Mexico Museum of Natural History and Science*
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*Raptorex* lived about 65 million years before *T. rex*, early in the superfamily's radiating divergence. Later forms, like *Kileskus* and , would be very different from the tyrant lizard. Yet its body plan is practically identical, a roughly horse-sized replica of the tyrant king. "These things didn't all form a smooth, gradual transition from small, older tyrannosaurs to big, more recent tyrannosaurs," said Brusatte. "They experimented." *Image:* Raptorex *in comparison to a* T. rex*./Todd Marshall.*
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The 20-foot-long *Alioramus* was "much more delicately constructed" than *T. rex*, said Brusatte. Yet the slender, long-boned dinosaurs were contemporaries of *T. rex*, and part of the same taxonomical subgroup. Brusatte has likened *Alioramus* to "ballerinas." *Image: Jason Brougham*
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Even as study of other tyrannosaurs proceeds at paleontologically breakneck pace, much is being learned about *T. rex* and its Asian counterpart, *Tarbosaurs*. These last and most magnificent *rex* species lived about 30 years, growing at fantastic rates. Their skulls could, not surprisingly, handle almost inconceivably high stresses. They scavenged as well as hunted, and ate each other. They could be feathered. As it turns out, they likely couldn't run fast, topping out around 11 miles per hour. Fortunately that was not known before *Jurassic Park*. *Image: Scott Kinmartin, Flickr.*
