title: Complex dental structure and wear biomechanics in hadrosaurid dinosaurs.
abstract: Mammalian grinding dentitions are composed of four major tissues that wear differentially, creating coarse surfaces for pulverizing tough plants and liberating nutrients. Although such dentition evolved repeatedly in mammals (such as horses, bison, and elephants), a similar innovation occurred much earlier (~85 million years ago) within the duck-billed dinosaur group Hadrosauridae, fueling their 35-million-year occupation of Laurasian megaherbivorous niches. How this complexity was achieved is unknown, as reptilian teeth are generally two-tissue structures presumably lacking biomechanical attributes for grinding. Here we show that hadrosaurids broke from the primitive reptilian archetype and evolved a six-tissue dental composition that is among the most sophisticated known. Three-dimensional wear models incorporating fossilized wear properties reveal how these tissues interacted for grinding and ecological specialization.
authors.affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA. gerickson@bio.fsu.edu
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Erickson
authors.forename: Brandon A
authors.initials: BA
authors.lastname: Krick
authors.forename: Matthew
authors.initials: M
authors.lastname: Hamilton
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Bourne
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
authors.forename: Erica
authors.initials: E
authors.lastname: Lilleodden
authors.forename: W Gregory
authors.initials: WG
authors.lastname: Sawyer
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000502:physiology*; D006244:Hardness; D008409:Mastication; D014070:Tooth / Q000648:ultrastructure*; D057085:Tooth Wear / Q000503:physiopathology*