Gigantic, long-necked, plant-eating sauropod dinosaurs flourished in terrestrial ecosystems for 150 million years during an episode of dramatic continental fragmentation. Titanosauria is the most diverse (40+ species), long-lived, and widely distributed sauropod lineage, but its evolutionary relationships remain poorly understood. This study will survey the global diversity of titanosaur anatomy and bone microstructure to resolve questions of titanosaur evolution and life history, and development. Anatomical data we collect will allow construction of the first well-supported hypothesis of titanosaur genealogy. Bone microstructural data will allow examination of growth rates and developmental traits across a diverse range of titanosaurs, which include gigantic and dwarf forms. Synthesis of these data will allow assessment of body size evolution and life history traits within Titanosauria, which will be central to future examinations of the evolution of titanosaur feeding specializations, locomotion, and paleobiogeography. The global nature of this project compels collaboration with international colleagues and students. Published papers and online resources will allow international researchers to access our data and results. Training undergraduate and graduate students is a priority, and funding will support graduate and undergraduate students for the duration of the project. The PIs are committed to public dissemination of research results via museum exhibits, public-friendly websites, and lectures.