New Antarctic findings of Upper Cretaceous and lower Eocene loons

[Ben Creisler <bcreisler@gmail.com>]

Ben Creisler
bcreisler@gmail.com



A new paper:



Carolina Acosta Hospitaleche & Javier N. Gelfo (2015)
New Antarctic findings of Upper Cretaceous and lower Eocene loons
(Aves: Gaviiformes).
Annales de Paléontologie (advance online publication)
doi:10.1016/j.annpal.2015.10.002
http://www.sciencedirect.com/science/article/pii/S0753396915000671



The new remains of Gaviiformes collected from the Maastrichtian
Sandwich Bluff Member (López de Bertodano Formation in Vega Island),
the Maastrichtian Klb 9 (López de Bertodano Formation in Seymour
Island), the Maastrichtian Snow Hill Formation (Vega Island), and the
Ypresian Submeseta Formation (Seymour Island), Antarctica, are
described. A specialized foot-propelled diving morphology is already
present in the Antarctic Polarornis gregorii, the Chilean Neogaeornis
wetzelli and the new specimens here reported, suggesting that such
diving skills were developed at least since the Upper Cretaceous. The
occurrence of Gaviiformes in the Southern Hemisphere during the Upper
Cretaceous–lower Eocene times is consistent with recent phylogenetic
proposals relating this group to Sphenisciformes and
Procellariiformes, birds already recorded in Antarctica. The fossil
record also supports the idea that the hemisphere displacement
observed in Gaviiformes could be a response to increasing competition
for resources with Sphenisciformes. The phylogenetic proximity of
penguins and loons plus their similar trophic behavior, suggest that
competitive exclusion could have triggered the gaviiform migration to
the Northern Hemisphere and explain their extinction from Southern
continents.