In Depth
As a member of the Brontornithinae group of terror birds Physornis was one of the larger and more robust members of the larger group, the Phorusrhacidae. As such it would have been related to Paraphysornis and Brontornis, and living during the Oligocene it was one of the earliest terror birds to roam and hunt in South America.
Further Reading
Further reading- Sur les oiseaux fossiles de Patagonie; et la faune mammalogique des couches � Pyrotherium. – Boletin del Instituto Geographico Argentino 15:501-660. – F. Ameghino – 1894.- Systematic revision of the Phorusrhacidae (Aves: Ralliformes). – Pap. Avulsos Zool. (S�o Paulo) 43(4). – H.M.F. Alvarenga & E. H�fling – 2003.
