March of the Fossil Penguins

Fossil penguin discoveries and research

A Surprising Advanced Paleocene Penguin

with 2 comments

How old are penguins? A new article reports some of the most ancient fossils yet, and discuss their implications of penguin evolution. The bones in question are elements of the hind limb: the good old tarsometatarsus (the bone that forms the main body of the foot) and several phalanges (toe bones).  They were discovered in New Zealand in the Waipara Greensand. which is the rock unit that yielded  Waimanu manneringiBoth fossils are about 61 million years old, making them the oldest penguins known.

Despite being the same age as Waimanu manneringi, the new fossils are more “penguiny”, at least when it comes to the foot morphology. Whereas Waimanu manneringi has a slender tarsometatarsus with a raised articulation for the second toe like many non-penguin birds, the new fossil has a much stouter tarsometatarsus that resembles penguins that are several million years younger. The heftiness suggests it might belong to a much heavier bird than Waimanu manneringi. Overall, a number of fine features suggest the new Waipara penguin occupies a branch on the evolutionary tree that is one step closer to modern penguins than any other species swimming around 61 million years ago (though to clear it was still a very distant relative of any living species).

penguin-press-1

Foot bones of a new fossil penguin from the Waipara Greensand (left) compared to the same bones from an Emperor Penguin (right). Photo courtesy Dr. Gerald Mayr.

The authors of the new paper suggest that there must have been more than just 5 million years for such a variety of penguins to evolve, pushing the origin of penguins into the Cretaceous Period. Does this mean we are going to eventually find penguins in rocks from the Cretaceous Period?  Personally, I am skeptical we will find a flightless penguin that old.  We have found tons of penguin fossils from the Paleogene Period, but not a single such bone from the Cretaceous Period. So, it seems likely penguin evolved into flightless wing-propelled divers after the K-Pg mass extinction, which wiped out the dinosaurs and marine reptiles like plesiosaurs and mosasaurs. It is of course possible that the flying ancestors of penguins were roaming around during the Cretaceous, though this would be  harder to prove because the delicate fossil bones of flying birds have much less of a chance of being preserved than the dense bones of diving birds. That would be quite a find.

 

Reference:

Mayr, G., De Pietri, V.L. & Paul Scofield. 2017. A new fossil from the mid-Paleocene of New Zealand reveals an unexpected diversity of world’s oldest penguins.  The Science of Nature 104:9.

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Written by Dan Ksepka

March 3, 2017 at 10:25 am

Posted in Uncategorized

2 Responses

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  1. Is anyone looking at Neogaeornis and the half-fictitious Polarornis again?

    I’m very skeptical about arguments from a presumed speed of morphological evolution, especially across a mass extinction event; but if you’re looking for candidates for Cretaceous penguins, here they are.

    David Marjanović

    March 3, 2017 at 4:57 pm

    • Neogaeornis is hard to pin down given there is only a partial bone available. However, it certainly appears to be a foot-propelled diver and I would suspect early penguins to be fully wing-propelled (though volant) without strong foot-propelled diving adaptations. Polarornis would be a great specimen except almost nothing in the paper is supported by the actual fossil, which has regrettably been so badly reconstructed that much of the morphology is now hard to observe. I’m pretty sure it is neither a loon not a penguin though,

      Dan Ksepka

      March 3, 2017 at 5:20 pm


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