"Purussaurus" is one of the largest known crocodyliformes ever to have existed. Three other extinct crocodyliformes, "Sarcosuchus", "Deinosuchus", and "Rhamphosuchus" had similar body sizes. "Sarcosuchus" and "Deinosuchus" had similar proportions, but both were geologically much older, dating from the Early and Late Cretaceous, respectively. One study also indicates that "Purussaurus" may have been heavier than either "Sarcosuchus" or "Deinosuchus," as it had a much broader, shorter snout and this would require a thicker, stronger neck to support the larger head. "Rhamphosuchus" lived around the same time as "Purussaurus", but was slightly smaller, had a more gharial-like snout and lived in India. During the summer of 2005, a Franco-Peruvian expedition (the Fitzcarrald expedition) found new fossils of "Purussaurus" in the Peruvian Amazon (600 km from Lima).