Ontogeny and the fossil record: what, if anything, is an adult dinosaur? - PubMed (original) (raw)

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Ontogeny and the fossil record: what, if anything, is an adult dinosaur?

David W E Hone et al. Biol Lett. 2016 Feb.

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.

Keywords: adult; dinosauria; growth; histology; juvenile; subadult.

© 2016 The Author(s).

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Figures

Figure 1.

Figure 1.

A tableau of Tyrannosaurus rex skeletal reconstructions, on display at the Natural History Museum of Los Angeles County. The largest individual represents typical adult size for the taxon—current mainstream scientific consensus considers them all different ontogenetic stages of T. rex but the smaller specimens were originally referred to different genera. Photo: DWEH. (Online version in colour.)

Figure 2.

Figure 2.

Various methods that may be used to determine the age/ontogenetic status of a given dinosaur specimen. Central image is a reconstruction of the skeleton of an adult ceratopsian Zuniceratops, with surrounding indications of maturity (taken from multiple sources and do not necessarily relate to this taxon). (a) Development of sociosexual signals (adult left, juvenile right—modified from [9]), (b) surface bone texture (traced from [17]), (c) large size, represented here by an ilium of the same taxon that is considerably larger than that of a known adult specimen, (d) reproductive maturity, here based on the presence of medullary bone here shown below the black arrow (traced from [18]), (e) fusion of the neurocentral arch—location of the obliterated synchondrosis indicated by black arrow (traced from [19]), (f) asymptote of growth based on multiple species indicated by black arrow (based on [20]). Central image by Julius Csotonyi, used with permission. (Online version in colour.)

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References

    1. Ralph CJ, Geupel G, Pyle P, Martin T, DeSante D. 1993. Handbook of field methods for monitoring landbirds. General Technical Report PSW-GTR-144-www. Albany, CA: Pacific Southwest Research Station, Forest Service U.S. Department of Agriculture.
    1. Dunham AE, Morin PJ, Wilbur HM. 1988. Methods for the study of reptile populations. In Biology of the Reptilia, vol. 16. Ecology B: defense and life history, pp. 331–386. New York, NY: Alan R. Liss, Inc.
    1. Chiappe L, Dingus L, Jackson F, Grellet-Tinner G, Aspinall R, Clarke J, Coria R, Garrido AC, Loope D. 2000. Sauropod eggs and embryos from the Late Cretaceous of Patagonia. In First Int. Symp. on Dinosaur Eggs and Babies, Isona I Conca Dellà, Catalonia, Spain. Extended Abstracts (eds AM Bravo, T Reyes), pp. 23–29. Lleida: Impremta Provincial de la Diputació de Lleida.
    1. Horner JR, Padian K, de Ricqlès A.. 2001. Comparative osteohistology of some embryonic and perinatal archosaurs: developmental and behavioral implications for dinosaurs. Paleobiology 27, 39–58. (10.1666/0094-8373(2001)027<0039:COOSEA>2.0.CO;2) - DOI
    1. Horner JR, de Ricqlès A, Padian K. 2000. Long bone histology of the hadrosaurid dinosaur Maiasaura peeblesorum: growth dynamics and physiology based on an ontogenetic series of skeletal elements. J. Vertebr. Paleontol. 20, 115–129. (10.1671/0272-4634(2000)020]0115:LBHOTH]2.0.CO;2) - DOI

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