The Why

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I focus on studying and understanding the forelimbs of dinosaurs because they played so many diverse roles from grasping to body support. This involves everything from fossil fieldwork to the study of living reptiles, birds, and mammals as models. I'm particularly interested in the evolution of the forelimb in sauropod dinosaurs ("brontosaurs"), the giant long-necked plant-eaters of the Age of Dinosaurs.

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How I Helped Discover Three New Dinosaurs

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The ancestors of sauropods were bipeds, but as they evolved larger body sizes they dropped back down onto all-fours, transforming their arms into forelegs. I was privileged to work with a team of scientists, students, and volunteers via National Geographic-sponsored field work in South Africa that led to the discovery of three new dinosaur species that highlight this transition.

 

• Aardonyx celestae, a transitional sauropodomorph dinosaur (almost a sauropod but not quite) that sheds light on the evolutionary transformation of the common ancestor of sauropods from a bipedal plant eater to larger, quadrupedal, bulk-browsing herbivores.

• Arcusaurus pereirabdolurm, a juvenile, primitive sauropodomorph that suggests the traditional “prosauropods” were not dead yet in the Early Jurassic, and still were part of the larger dinosaurian fauna.

• Pulanesaura eocolum, a true early sauropod whose neck allowed it to do what the later sauropods were really good at: standing in one place and cropping vegetation with its tiny head.

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X-ray Reconstruction of Moving Morphology (XROMM)

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More recently, in the laboratory, my colleagues, students, and I are using using a technique called XROMM (X-ray Reconstruction of Moving Morphology) to non-invasively study how the bones in the forelimbs of living birds, reptiles, and mammals move to test hypotheses about the evolution of forelimb posture in the ancestors of mammals and dinosaurs.