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Congrats Nic Campione, Ph. D.

June 15, 2013
Dr. Nicolas Campione measuring hadrosaur bones in China.

Dr. Nicolas Campione measuring hadrosaur bones in China.

Congrats to Nic Campione for successfully defending his PhD thesis, which he handed in last week.  Nic’s thesis was entitled “Inferring Body Mass in Extinct Terrestrial Vertebrates and the Evolution of Body Size in a Model-Clade of Dinosaurs (Ornithopoda)” (see abstract  below).

ABSTRACT– Organismal body size correlates with almost all aspects of ecology and physiology. As a result, the ability to infer body size in the fossil record offers an opportunity to interpret extinct species within a biological, rather than simply a systematic, context. Various methods have been proposed by which to estimate body mass (the standard measure of body size) centering on two main methods: volumetric reconstructions and extant scaling models. The latter models are particularly contentious when applied to extinct terrestrial vertebrates, particularly stem-based taxa for which living relatives are difficult to constrain, such as non-avian dinosaurs and non- therapsid synapsids, resulting in the use of volumetric models that are highly influenced by researcher bias. However, criticisms of scaling models have not been tested within a comprehensive extant dataset. Based on limb measurements of 200 mammals and 47 reptiles, linear models were generated between limb measurements (length and circumference) and body mass to test the hypotheses that phylogenetic history, limb posture, and gait drive the relationship between stylopodial circumference and body mass as critics suggest. Results reject these and instead recover a highly conserved relationship that provides a robust method to estimate body mass in extinct quadrupedal tetrapods. The constrained model is then used to derive a mathematical correction that permits the body mass of bipedal taxa to be estimated from the quadrupedal-based equation. These equations thus form the empirical baseline dataset with which to assess the accuracy of mass estimates derived from volumetric reconstructions, which, although subjective, are crucial for interpreting biomechanical and physiological attributes in extinct forms. The models developed through this research provide accurate and consistent estimates of body size in terrestrial vertebrates, with important implications for generating large datasets aimed at reconstructing macroevolutionary patterns of body size in association with changing Earth systems.

Nic has already accepted a postdoctoral post at Uppsala University in Sweden, where he will be working with Drs. Ben Kear and Per Alhberg on Palaeozoic fish diversity and evolutionary dynamics- as well as dinosaur work. All of us in the lab wish him the very best in his new post!

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