title: Ontogeny and the fossil record: what, if anything, is an adult dinosaur?
abstract: Identification of the ontogenetic status of an extinct organism is complex, and yet this underpins major areas of research, from taxonomy and systematics to ecology and evolution. In the case of the non-avialan dinosaurs, at least some were reproductively mature before they were skeletally mature, and a lack of consensus on how to define an 'adult' animal causes problems for even basic scientific investigations. Here we review the current methods available to determine the age of non-avialan dinosaurs, discuss the definitions of different ontogenetic stages, and summarize the implications of these disparate definitions for dinosaur palaeontology. Most critically, a growing body of evidence suggests that many dinosaurs that would be considered 'adults' in a modern-day field study are considered 'juveniles' or 'subadults' in palaeontological contexts.
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London, UK d.hone@qmul.ac.uk.
authors.forename: David W E
authors.identifier: http://orcid.org/0000-0002-5668-4603
authors.initials: DW
authors.lastname: Hone
authors.affiliation: Raymond M. Alf Museum of Paleontology, Claremont, CA, USA.
authors.forename: Andrew A
authors.identifier: http://orcid.org/0000-0002-6930-2002
authors.initials: AA
authors.lastname: Farke
authors.affiliation: Department of Anatomy, College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine, Western University of Health Sciences, Pomona, CA, USA.
authors.forename: Mathew J
authors.identifier: http://orcid.org/0000-0001-6082-3103
authors.initials: MJ
authors.lastname: Wedel
mesh_terms: D000818:Animals; D025061:Dinosaurs / Q000033:anatomy & histology / Q000254:growth & development*; D005580:Fossils / Q000033:anatomy & histology; D010163:Paleontology / Q000379:methods*
keywords: adult; dinosauria; growth; histology; juvenile; subadult