Struthionidae

Struthionidae (; ) is a family of flightless birds, containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich, both in the genus Struthio, which also contains several species known from Holocene fossils such as the Asian ostrich. The common ostrich is the more widespread of the two living species, and is the largest living bird species. The extinct genus Pachystruthio from the Late Pliocene-Early Pleistocene of Eurasia is one of the largest birds ever.

Pachystruthio is a genus of extinct bird which lived in Eurasia from the Late Pliocene to the Middle Pleistocene. Its fossils have been found in Hungary, Greece Crimea, Georgia, and China. The genus contains three species: P. pannonicus (the type species), P. dmanisensis, and P. transcaucasicus, which were all formerly placed with the ostrich genus, Struthio. An incomplete femur from the Nihewan Formation (China) has been assigned to Pachystruthio indet. P. dmanisensis has been estimated standing 3.5 meters (11.5 feet) tall and weighing up to 450 kg (990 lb), making it much larger th