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Text: "Puijila" in Inuktitut. Puijila: A Prehistoric Walking Seal. Photo collage: Scheuchzer's cotton-grass (Eriophorum scheuchzeri), the research team at work in the field, a reconstruction of the Puijila darwini fossil, an ejector block in the Haughton Crater, two palaeontologists shaking a dry screen.
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Text: "Inuktitut" in Inuktitut syllabics.
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In the Lab

Old Fossils and Skeleton Rooms

Image 1) Overhead view of Puijila's bones laid out on a table; some are in boxes. Collection number NUFV405.

The Puijila specimen in Natalia Rybczynski's office.

The next task was to try to identify the animal. Is it a species already known to science? What other animals or groups would it be related to?

Working with the bones in the field made a strong first impression. Dawson thought the skeleton looked similar to a fossil animal that she had seen before: Potamotherium.

Potamotherium had been known to science since 1833, but no one was quite sure what it was. The most recent idea was that it was a strange otter, or a member of a dead-end lineage related to the musteloids (the group that includes otters, weasels and badgers).

The skeletal remains of Potamotherium are well represented in the Naturhistorisches Museum Basel, in Switzerland. Dawson visited the collections there and found some similarities between Pomatotherium and the new fossil. However it also became apparent that compared to Potamotherium, the carnivore from the crater appeared more primitive.

Image 2) Two hands: one holding a Steller sea lion (Eumetopias jubatus) skull (collection number CMNMA2609) and the other holding part of the Puijila darwini skull (NUFV405). Underneath is an open collection-storage drawer containing bones of a harp seal (Pagophilus groenlandicus, collection number CMNMA75421).

In Nature's Osteological Reference collection, Natalia compares Puijila's skull (in her left hand) to that of a Steller sea lion (right) and a harp seal (in the drawer).

Working in the collections of the Canadian Museum of Nature, Rybczynski found that many aspects of the skeleton appeared otter-like. But, scouring relevant scientific papers for clues led Rybczynski and Dawson to some surprising results. They found that some researchers had suggested that Potamotherium might be a relative of pinnipeds (true seals, sea lions and the walrus).

In autumn 2007, Rybczynski, Dawson and Gilbert packed up the fossil skeleton and went to New York. There, they met with fossil carnivore expert Richard Tedford, of the American Museum of Natural History. They compared the Arctic carnivore with key fossils in the AMNH's collections. And, of course, they looked at even more scientific papers.

They put together a data-set comprising a list of carnivore species (mostly known from fossils) and their skeletal characteristics. The data-set was analyzed to determine how the animals were likely to be related. The results of the analysis showed that both the new carnivore and Potamotherium were more closely related to pinnipeds than to any other carnivore group.

Image 3) The braincase on the ground, with a scale bar beside. Puijila darwini, collection number NUFV405.

The braincase on the ground where it was found.

During the 2008 expedition to the Haughton Crater, the missing braincase of the new carnivore was found. The research process and analysis were repeated with the new evidence. The results were the same: this new carnivore was a basal pinniped.

Finally, it was time to name the animalPuijila darwini—and tell the world!

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Image 5) Natalia Rybczynski holding the braincase of Puijila darwini (collection number NUFV405).