Journal of Vertebrate Paleontology describes a bizarre 66 million-year-old mammal that provides profound new insights into the evolutionary history of mammals from the southern supercontinent Gondwana—recognized today as Africa, South America, Australia, Antarctica, the Indian subcontinent, and the Arabian Peninsula. Named Adalatherium, which, translated from the Malagasy and Greek languages means "crazy beast," it is described based on a nearly complete, exquisitely preserved skeleton, the most complete for any mammal yet discovered in the southern hemisphere prior to the extinction of the dinosaurs. The research, carried out over 20 years, demonstrates that Adalatherium was a "giant" relative to the mostly shrew- or mouse-sized mammals that lived during the Cretaceous period.