The classification presented here is based on work by the ornitho.... lower length

Fifteen species; in grasslands and brush; southern Europe, Asia, Africa, and Australia; body length 1119 cm. Fossil only; lower to middle Eocene; North America; 7 species known. Fossil only; lower Oligocene to lower Miocene; North America; 8 species known. Fossil only; upper Eocene to upper Miocene; eastern Asia; 2 species known. Twenty-one fossil and 15 Recent species; plains and marshes of the world, except South America; length about 79 to 150 cm. Fossil only; lower Oligocene to lower Pliocene; eastern Europe and Asia; 3 known species. Swamps and marshes of New World tropics and subtropics; 5 fossil and 1 Recent species; length 58 to 71 cm (in Recent forms). Three species, in lowland forest of South America; length 43 to 53 cm. About 56 fossil and 132 Recent species; principally in marshes; worldwide; length about 14 to 51 cm. Upper Eocene to lower Oligocene of Europe and North America; 8 species known. Three species; slow-flowing streams in tropical areas of Central and ! South America, Africa, and India and Southeast Asia; length 30 to 62 cm. One species; margins of woodland streams in Central and South America; length about 46 cm. Lower Oligocene to middle Miocene of Argentina and Uruguay; 2 species known. Lower Oligocene to middle Pliocene of Argentina; 4 species known. Lower Pliocene to lower Pleistocene of Argentina; 3 species known. Lower Miocene to lower Pleistocene; 10 species: 9 from Argentina, 1 from Florida. Lower Oligocene to middle Pliocene of Argentina; 9 species known. Two species; in grassland and brush, respectively, of east-central South America; length 76 to 92 cm. Cursorial, but strong flying birds of open plains of Eurasia, Africa and Australia; 3 fossil and 23 Recent species; length 37 to 132 cm. Lower Pliocene of Ukraine; 1 species known. lower length