Revista de la Asociación Geológica Argentina versión On-line
ISSN 1851-8249 Antarctic fossil birds can be confidently
assigned to modern orders and families, such as a goose-like
anseriform, two loon-like and a seriema-like, all recorded
before the K/T boundary at the López de Bertodano Fomation.
Also, the discovery of a ratite and a phororhacids from the
uppermost levels of the Submeseta Allomember (Late Eocene),
suggests that West Antarctica was functional to dispersal routes
obligate terrestrial birds. Representatives of Falconiformes
Polyborinae, Ciconiiformes, Phoenicoteriformes, Charadriiformes,
Pelagornitidae and Diomedeidae constitute the non-penguin avian
assemblages of the Eocene of La Meseta Formation. Fifthteen
Antarctic species of penguins have been described including the
oldest penguin of West Antarctica, Croswallia unienwillia. The
Anthropornis nordenskjoeldi Biozone (36.13 and 34.2 Ma, Late
Eocene) is characterized by bearing one of the highest
frequencies of penguin bones and the phospatic b