Angiosperms were largely present in the formation, based on fossils of cornaceans and fossilized fruits at several localities. Contemporary paleofauna Achillobator shared its surroundings in the Bayan Shireh Formation with other paleofauna such as the medium-sized theropods Erlikosaurus and Segnosaurus, Garudimimus, and possibly Alectrosaurus; the heavy-built ankylosaurs Talarurus and Tsagantegia; the small marginocephalians Amtocephale and Graciliceratops; the hadrosauroid Gobihadros; and the large, long-necked sauropod Erketu. Non-dinosaur taxa was present as well, mostly compromising semiaquatic and terrestrial reptiles like the turtles Lindholmemys, Gobiapalone and "Trionyx"; and the crocodylomorph Paralligator. Fishes are also known from the formation, such as the shark Hybodus and the remains of osteichthyans at various localities. Mammals were extremely rare around the formation. Niche partitioning has been reported among Bayan Shireh species, such is the case of high browser therizinosaurids Erlikosaurus and Segnosaurus, or the grazer Talarurus and browser Tsagantegia. Erketu may have been the tallest herbivore of the paleofauna. See also Timeline of dromaeosaurid research References External links Eudromaeosaurs Fossil taxa described in 1999 Late Cretaceous dinosaurs of Asia Taxa named by Altangerel Perle Taxa named by Mark Norell Taxa named by James M. Clark