A peculiar anseriform (Aves: Anseriformes) from the Miocene of Gargano (Italy)

A new large representative of the Anseriformes, Garganornis ballmanni n. gen. et n. sp., from the Miocene of Gargano, Italy, is described from the distal end of a left tibiotarsus. G. ballmanni displays morphological features that are characteristic of the Anseriformes, but differs from all extant and fossil Anseriformes, as well as from taxa closely related to Anseriformes. G. ballmanni is characterized by a very wide and shallow fossa intercondylaris, a less pronounced difference in width of the lateral and medial condyle, reduced epicondyli, and a circular opening of the distal canal. G. ballmanni is larger than any living member of Anseriformes, and with an estimated body mass between 15.3 and 22.3 kg, it was most likely flightless. Although the observed similarities between G. ballmanni and basal taxa might indicate that G. ballmanni represents an insular relict of a stem lineage, it is considered more likely that G. ballmanni was a species of waterfowl highly adapted to a terrestrial lifestyle in an insular environment where mammalian carnivores are rare.