Additional Pelagornithidae remains from Seymour Island, Antarctica. (April 2020) - Acosta Hospitaleche, Carolina
Abstract: Two incomplete mandibles are assigned to Pelagornithidae given the presence of a well marked neurovascular furrow and the unique bony projections, or "pseudo-teeth", along the crista tomialis . Specimens IAA-Pv 175 from Ypresian levels of La Meseta Alloformation (Cucullaea I Allomember), and IAA-Pv 823 from Bartonian beds of the Submeseta Alloformation, in Seymour Island (Antarctic Peninsula, West Antarctica) corresponds to the morpho-type 1, previously proposed for Antarctic pseudo-tooth birds. The intermediate condition of the pseudo-teeth of these specimens reinforces the idea that diet changed from piscivory to molluscivory along the evolutive history of the group. Highlights: Two new mandibles of Pelagornithidae from Antarctica are reported. The new materials analyzed here extend the record of the pseudo-toothed belonging to morphotype 1 from the Ypressian to the Priabonian. The time of greatest diversification of pseudo-tooth birds in Antarctica (middle-late? Eocene) coincides with this evolutionary event on a global scale.