Tooth wear in juvenile and adult hadrosaurs: implications for parental care in Maiasaura

Juveniles of the hadrosaurian dinosaur Maiasaura peeblesorum exhibit different proportions of wear types in the dental batteries than seen in adult hadrosaurs. We interpret the wear types in hadrosaur teeth, by analogy with those of living mammalian herbivores, to be ‘shearing’ (indicative of trituration of fibrous food items such as mature leaves) and ‘crushing’ (indicative of trituration of more succulent, higher protein food items such as berries or nuts). Quantification of the dental wear patterns shows that juvenile maiasaurs exhibit significantly more crushing wear than adults. The proportions of shear to crush wear in the juveniles resembles that seen in extant mammals with a frugivorous/folivorous diet, whereas the proportions in the adults resemble those seen in extant mammals with a diet of high fiber content. We interpret these findings, in the light of other studies suggesting parental care through provisioning of young at the nest in maiasaurs, to mean that the adults may have been bringing food to the nest of a higher protein content than they themselves ate, behavior typical of certain extant birds. • Rapid growth in altricial maiasaur young would have required selective provisioning. • Nestling maiasaurs had worn dental batteries with more ‘crushing’ wear than adults. • % crushing wear reflects proportion of non-fibrous dietary items in extant mammals. • Wear indicates higher-quality, lower-fiber diet in maiasaur nestlings than adults. • Provisioning of young by adults with high quality food a bird-like behavioral trait.