Pachystruthio

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 than the modern ostrich and one of the largest known birds.

Although P. dmanisensis is known as the giant ostrich, its relationship to the extant ostriches of the genus Struthio is not clear.