dc.contributor.author	Griffin, Christopher T.	en
dc.contributor.committeechair	Nesbitt, Sterling J.	en
dc.contributor.committeemember	Freeman, Larry E.	en
dc.contributor.committeemember	Colbert, Matthew W.	en
dc.contributor.committeemember	Stocker, Michelle R.	en
dc.contributor.department	Geosciences	en
dc.date.accessioned	2016-12-12T19:13:35Z	en
dc.date.available	2016-12-12T19:13:35Z	en
dc.date.issued	2016-06-24	en
dc.description.abstract	Understanding the changes undergone during the life of an organism is often crucial to properly interpreting the evolutionary history of a group. For extinct organisms, this process can only be directly studied through growth series of fossils representing individuals at different stages of maturity. The growth patterns of the earliest dinosaurs (230–190 million years ago), in particular the morphological changes undergone during the life history of an individual (i.e., ontogeny) is poorly understood. To tackle this problem, I studied the changes undergone during growth of two early theropod dinosaurs, Coelophysis bauri and Megapnosaurus rhodesiensis. To reconstruct the growth of these dinosaurs I used ontogenetic sequence analysis (OSA). I found that, unlike living birds, early dinosaurs possessed an extremely high amount of intraspecific variation in growth. This variation had been previously interpreted as sexual difference; however, I found no evidence of this. Because this variation is widespread among early dinosaurs and their relatives, I hypothesize that this is the ancestral condition of dinosaurian growth, and that this was lost along the evolution to birds. These ontogenetic events are conserved through evolution, and I used this to assess the maturity of large Triassic theropods: I suggest that all known large-bodied Triassic theropods were still growing rapidly at death, and that the maximum body size of Triassic theropods was higher than previously supposed. Theropods were large before the end Triassic mass extinction, unlike what has been previously hypothesized.	en
dc.description.degree	Master of Science	en
dc.format.medium	ETD	en
dc.identifier.other	vt_gsexam:7691	en
dc.identifier.uri	http://hdl.handle.net/10919/73682	en
dc.publisher	Virginia Tech	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Ontogeny	en
dc.subject	variation	en
dc.subject	dinosaur	en
dc.subject	theropod	en
dc.subject	extinction	en
dc.title	The evolution of intraspecific variation, growth, and body size in early theropod dinosaurs	en
dc.type	Thesis	en
thesis.degree.discipline	Geosciences	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en

The evolution of intraspecific variation, growth, and body size in early theropod dinosaurs

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