Recent interpretations of the postcranial anatomy of sauropod dinosaurs differ about pneumatic features supporting an avian-like ventilatory system; the most conservative workers reject most postcranial pneumatizations as being unambiguous evidence of abdominal air sacs. Here we describe the first articulated dinosaur skeleton from Tunisia and refer it to a new rebbachisaurid sauropod, Tataouinea hannibalis gen. et sp. nov. The Tunisian specimen shows a complex pattern of caudosacral and pelvic pneumatization—including the first report of an ischial pneumatic foramen among Dinosauria—strongly supporting the presence of abdominal air sacs. Character optimization among Rebbachisauridae indicates that in the caudal vertebrae, pneumatization of the neural arches preceded that of the centra; in the pelvis, pneumatization of the bones adjacent to the sacrum preceded that of more distal elements. Tataouinea was more closely related to European nigersaurines than to otherwise Gondwanan rebbachisaurids; this supports an Afro-European route for rebbachisaurid dispersal.