Fossil Penguins at DinoFest

Recently I was invited to be a “DinoBite” speaker at the Utah Museum of Natural History’s Polar DinoFest. The event was held virtually his year due to COVID, but on the plus side that means I can post the whole talk on this blog. Check it out if you are interested in hearing about penguin evolution – and sorry for the sound quality, I had to tape this with my laptop!

A New Fossil Crested Penguin

Apologies to fossil penguin fans, as this blog has been slow to update with new penguin paleontology news due to the arrival of the authors daughter. It’s time to dive back into the world of prehistoric penguins, and what better way to start than discussing some exquisitely well-preserved fossils from a new species! I was lucky to be part of a team led by Dr. Daniel Thomas of Massey University that studied t

Recently, Eudyptes atatu joined the march of the fossil penguins. This species is the earliest member of the crested penguin group at just over three million years old. That’s not too terribly old compared to the 61 million year old Waimanu manneringi, but certainly ancient by human standards. Crested penguins all share golden head feathers that give them rather foppish appearances. There are between six and eight modern species of crested penguins, depending on whether the eastern rockhopper and the royal penguin are treated as full species.  There are also two previously known fossil species. Eudyptes calauina is known from just a few bones from South America.  Eudyptes warhami, from the Chatham Islands, has the unfortunate distinction of being the only penguin species wiped out by humans.

Life reconstruction of Eudyptes atatu by Simone Giovanardi of Massey University.

“Eudyptes” is an existing genus name meaning “good diver” in Greek. The species name “atatu” is based on the Māori “ata tū”, meaning dawn. This name recognizes that the new fossil species is the earliest member of the crested penguin group and therefore can tell us about the origins of these fantastic birds. Fossils of the species were discovered in the Taranaki region of the North Island of New Zealand and include almost every bone of the skeleton. Particularly lovely are three skulls of the species. These reveal that despite having a very similar body to modern crested penguins, Eudyptes atatu had a very slender beak. The mandible (lower jaw bone) is quite slender, as opposed to the very deep jaw bone in modern Eudyptes species. This suggests that Eudyptes atatu may have been less well-adapted to catching small shoaling prey species like krill. In living crested penguins, the tongue is very large and bristle-covered, which helps hold onto small prey snapped while swimming through swarms of krill.

Fossil material Eudyptes atatu with the skull of a modern Snares crested penguin (Eudyptes robust) for comparison. Note the slender beak of the fossil compared to the deep beak of the modern species. Figure from Thomas et al. (2020).

The new fossils suggest the deep bill of modern Eudyptes evolved about 2-3 million years ago (very recently by geological standard). This could reflect changing conditions in the southern oceans around this same time. Beginning in the Pliocene, wind-driven upwelling of cold bottom waters transformed the oceanic food web by triggering a boom in krill biomass. The appearance of such a rich food source may have given deeper-billed penguins an advantage as they were better suited for harvesting lots of tiny prey items. A much more extreme example is scene in baleen whales, which appear to become super-sized in response to these same new feeding opportunities. Eudyptes atatu thus provides an interesting data point for interpreting big picture events as well as a neat little branch on the evolutionary tree of penguins.

Reference:

Thomas, D.B., A.J.D. Tennyson, R.P. Scofield, T.A. Heath, W. Pett, and D.T. Ksepka. 2020. Ancient crested penguin constrains timing of recruitment into seabird hotspot Proceedings of the Royal Society B 287: 20201497.