Mark Norell is the direct discoverer of enigmatic theropods Shuvuuia and Mononykus, the discovery of Ukhaa Tolgod, the richest Cretaceous fossil locality in the world, the first embryo of a theropod dinosaur, the description of dinosaurs with feathers, and the first indication of dinosaur nesting.
Animals that may have shared the same habitat with Tsaagan include Protoceratops, Shuvuuia, the small mammal Zalambdalestes, the multituberculate mammal Kryptobaatar, as well as several lizards and two yet-undescribed species of troodontid and dromaeosaurid.