Penguin cranial remains from the Eocene La Meseta Formation, Isla Marambio (Seymour Island), Antarctic Peninsula CAROLINA ACOSTA HOSPITALECHE and NADIA HAIDR

Widely accepted ideas about trophic preferences of early penguins suggest that all Eocene sphenisciforms were piscivorous. However, recent findings from the La Meseta Formation (Eocene) of Antarctica, support the presence of at least two different morphotypes that may have evolved as a niche partitioning strategy, which is consistent with the high diversity recorded. The first of them corresponds to a medium-large sized penguin, resembling the Neogene species in configuration. Another morphotype is represented by extremely large penguins with very long and slender bills, clearly linked to fish catching habits.