title: Extraordinary diphyodonty-related change in dental function for a tooth of the extinct marsupial Ekaltadeta ima (Propleopinae, Hypsiprymnodontidae).
abstract: A time-dependent, fundamental change in function for a sectorial tooth in a group of extinct, propleopine kangaroos is reported. In juvenile Ekaltadeta ima (Marsupialia, Hypsiprymnodontidae, Propleopinae) the second premolar (P2) functions as a serrated blade at the anterior end of the cheek tooth row. In adults, this tooth drops far below the occlusal plane of the cheek tooth row where it assumes a completely different function, that of a buttress, anterolingual to the base of the crown of the much larger, newly erupted third premolar (P3). This pattern of diphyodonty-related change in dental function is unique within Mammalia. It also represents an extraordinary example of biological recycling of a normally discarded tooth.
authors.affiliation: School of Biological Science, University of New South Wales, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Wroe
authors.forename: M
authors.initials: M
authors.lastname: Archer
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001641:Bicuspid / Q000033:anatomy & histology* / Q000502:physiology; D005580:Fossils; D007614:Macropodidae / Q000033:anatomy & histology*; D010161:Paleodontology