Palaeobiology: Herbivorous diet in an ornithomimid dinosaur

In 1997, twelve well-articulated skeletons of an ornithomimid dinosaur from the Upper Cretaceous Ulansuhai Formation in China were discovered. Each skeleton contained a preserved gastrolith mass inside the ribcage that was attached on the medial surface of the articulated dorsal ribs and gastralia. The occurrence and characteristics of gastrolith masses in this ornithomimid indicate that these non-avian toothless theropods may have had gizzards and been herbivores, like modern herbivorous birds that use grit to grind up plant matter.