<p><strong>January 19, 2010—</strong>Two <a id="c.y1" title="predatory dinosaurs known as Guanlong wucaii" href="http://news.nationalgeographic.com/news/2006/02/0208_060208_dinosaur_china.html">predatory dinosaurs known as <em>Guanlong wucaii</em></a> struggle in a muddy pit in a painting of <a id="v.v3" title="China" href="http://travel.nationalgeographic.com/travel/countries/china-guide/">China</a>'s Xinjiang region during the late Jurassic period, about 160 million years ago. <em>Guanlong,</em> which means "crested dragon," was a small theropod, a group of bipedal raptors from the lineage that includes <em>Tyrannosaurus rex.</em></p><p>The painting depicts one of China's mysterious dinosaur "death pits"—3.5- to 6.5-foot-deep (1- to 2-meter-deep) depressions filled with the largely complete skeletons of several small theropod species. Now a new study has pinpointed a possible origin of the traps: They may be the mud-filled footprints of the 20-ton sauropod dinosaur <em>Mamenchisaurus</em>.</p><p><em>—Reporting by Brian Handwerk</em></p>

Dinosaur Death Pit

January 19, 2010—Two predatory dinosaurs known as Guanlong wucaii struggle in a muddy pit in a painting of China's Xinjiang region during the late Jurassic period, about 160 million years ago. Guanlong, which means "crested dragon," was a small theropod, a group of bipedal raptors from the lineage that includes Tyrannosaurus rex.

The painting depicts one of China's mysterious dinosaur "death pits"—3.5- to 6.5-foot-deep (1- to 2-meter-deep) depressions filled with the largely complete skeletons of several small theropod species. Now a new study has pinpointed a possible origin of the traps: They may be the mud-filled footprints of the 20-ton sauropod dinosaur Mamenchisaurus.

—Reporting by Brian Handwerk

Illustration courtesy Michael Skrepnik

Pictures: Dinosaur "Death Pits" May Be Fossil Footprints

Following in a giant dinosaur's footsteps could be fatal—but not for the reasons you might suspect. A new study suggests that death traps filled with rare raptor fossils may have been created when a behemoth strolled across ashy mud.

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