Cladornis
Appearance
Cladornis is a genus of Pelecaniformes descripted by Ameghino nel 1895, with one species Cladornis pachypus lived between 33.9 to 23.03 Ma and found only at Gulf of San Jorge (Oligocene of Argentina)
References http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=53634