Archive for March 2014
In a recent article in PLoS ONE, and colleagues announced the discovery of a new fossil penguin species, Eudyptes calauina. This new species hails from the Horcon locality, along the southern coast of Chile. The fossils are from the Late Pliocene, about 2-3 million years old. Flipper and leg bones were discovered, several of them in very nice condition. The authors completed a phylogenetic analysis, designed to use characteristics of the bones to place the new species within the evolutionary tree of penguins. The results show the new species belongs to the crested penguin genus Eudyptes, which is represented by seven living species (eight if you split the Rockhoppers more finely). These penguins are defined by their bright yellow head plumes, which are present in both males and females. Interestingly, there are no crested penguins in the region today. Banded Spheniscus penguins dominate, including Magellanic Penguins (Spheniscus magellanicus) and also a few Humboldt Penguins (Spheniscus humboldti), which have their main strongholds to the north. Besides extending the geographic range of the Eudyptes group, the new species is larger than any of the living species. Together with previous discoveries of stiff-tailed Pygoscelis penguin fossils in Chile, fossil excavations are revealing a major turnover in penguin faunas along the coats of South America within just the past few million years. Given that penguins have been hanging out on the continent for over 40 million years, this can be viewed as a rapid change.
One of the reasons this new discovery is important is that it tells us more about the relationship between ocean currents and seabird faunas. The Humboldt Current plays a major role in defining ecosystems along the Pacific coast of South America by providing nutrient rich cold-water upwelling. Today, the seabird communities of northern Chile and Peru are quite distinct from those in southern Chile, with a general trend towards more cold-adapted birds taking over as one moves south. We know a lot about the history of penguins in the northern part of Chile and Peru from fossils such as the “bobble-headed” penguin Spheniscus megaramphus, which lived around the same time as Eudyptes calauina, as well as much older fossils like Perudyptes devriesi. However, up until now we have had a very poor understanding of what types of penguins where living in the southern Pacific coastal area. Eudyptes calauina heralds a pattern differences that many paleontologists suspect will grow more profound as more field work is conducted, reinforcing the role of ocean currents in enforcing boundaries between species assemblages.
Chávez Hoffmeister M, Carrillo Briceño JD, Nielsen SN (2014) The Evolution of Seabirds in the Humboldt Current: New Clues from the Pliocene of Central Chile. PLoS ONE 9(3): e90043. doi:10.1371/journal.pone.0090043