부산대학교 도서관

In September 2001, large ornithopod footprints were found in the Nemegt Formation at the locality known as Nemegt in the Gobi of Mongolia. Additional hadrosaur ichnites, plus footprints of sauropods and theropods, have been recovered since then. The Nemegt Formation is known for the number and diversity of dinosaur skeletons found there, but footprints have never before been reported. Footprints were noted in three horizons within the formation, and occur at the top of upward-fining successions of floodplain sandstones and mudstones of a meandering fluvial paleoenvironment. Most of the footprints are preserved as natural casts that show good preservation of detail. Skin impressions are found on some, and many have slide marks. The vast majority of the footprints can be identified as having been made by Saurolophus, but two footprints each of Tarbosaurus and Opisthocoelicaudia were also recovered. Three hadrosaur footprints were found in the quarry of a Tarbosaurus skeleton. It appears that after the Tarbosaurus had died and been partially buried, its skeleton was trampled by a hadrosaur. The overwhelming domination of hadrosaurs at the footprint levels suggests there are preservational biases acting on the fossilization of Nemegt skeletons to produce abnormally high predator/prey ratios. [ABSTRACT FROM AUTHOR]