title: Palaeontology. The beaks of ostrich dinosaurs.
abstract: Primitive ornithomimids, a ubiquitous group of specialized Cretaceous dinosaurs nested within a clade of predominantly carnivorous theropods, are known to have had teeth, whereas derived ornithomimids had an edentulous beak, which has prompted speculation about their dietary habits. Here we describe two new ornithomimid specimens in which soft-tissue structures of the beak have been preserved. These creatures probably used their beaks to strain food sediment in an aqueous environment, rather than for predation on large animals.
authors.affiliation: American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024-5192, USA. norell@amnh.org
authors.forename: M A
authors.initials: MA
authors.lastname: Norell
authors.forename: P J
authors.initials: PJ
authors.lastname: Makovicky
authors.forename: P J
authors.initials: PJ
authors.lastname: Currie
mesh_terms: D000818:Animals; D001502:Beak / Q000033:anatomy & histology*; D005580:Fossils; D012104:Reptiles / Q000033:anatomy & histology* / Q000145:classification