Liptornis hesternus is a fossil bird of uncertain affinities. It was described by Argentine palaeontologist Florentino Ameghino in 1894 from a large cervical vertebra from the Middle Miocene of Patagonia. At the time it was referred to the Pelecanidae, though this is questionable. In his 1933 palaeornithological review, Lambrecht referred it only to the superfamily Sulides without placing it in a family. A later study has suggested family Anhingidae.