title: Wear biomechanics in the slicing dentition of the giant horned dinosaur Triceratops.
abstract: Herbivorous reptiles rarely evolve occluding dentitions that allow for the mastication (chewing) of plant matter. Conversely, most herbivorous mammals have occluding teeth with complex tissue architectures that self-wear to complex morphologies for orally processing plants. Dinosaurs stand out among reptiles in that several lineages acquired the capacity to masticate. In particular, the horned ceratopsian dinosaurs, among the most successful Late Cretaceous dinosaurian lineages, evolved slicing dentitions for the exploitation of tough, bulky plant matter. We show how Triceratops, a 9-m-long ceratopsian, and its relatives evolved teeth that wore during feeding to create fullers (recessed central regions on cutting blades) on the chewing surfaces. This unique morphology served to reduce friction during feeding. It was achieved through the evolution of a complex suite of osseous dental tissues rivaling the complexity of mammalian dentitions. Tribological (wear) properties of the tissues are preserved in ~66-million-year-old teeth, allowing the creation of a sophisticated three-dimensional biomechanical wear model that reveals how the complexes synergistically wore to create these implements. These findings, along with similar discoveries in hadrosaurids (duck-billed dinosaurs), suggest that tissue-mediated changes in dental morphology may have played a major role in the remarkable ecological diversification of these clades and perhaps other dinosaurian clades capable of mastication.
authors.affiliation: Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL 32306-4295, USA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Erickson
authors.affiliation: Department of Mechanical Engineering, Lehigh University, 19 Memorial Drive West, Bethlehem, PA 18015, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sidebottom
authors.affiliation: Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL 32306-4295, USA.
authors.forename: David I
authors.initials: DI
authors.lastname: Kay
authors.affiliation: Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Turner
authors.affiliation: Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Ip
authors.affiliation: Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of Florida, 328 Mechanical Engineering Building, Gainesville, FL 32611, USA.
authors.forename: W Gregory
authors.initials: WG
authors.lastname: Sawyer
authors.affiliation: Department of Mechanical Engineering, Lehigh University, 19 Memorial Drive West, Bethlehem, PA 18015, USA.
authors.forename: Brandon A
authors.initials: BA
authors.lastname: Krick
keywords: Dinosauria; Evolution; Feeding; Material Properties; Paleontology; Tribology; Triceratops; Wear