Otter-like fossil reveals early seal evolution

Monday, April 27th, 2009

Otter-like fossil reveals early seal evolution:

Rybczynski, a researcher at the Canadian Museum of Nature in Ottawa, and colleagues from the United States report the find in Thursday’s issue of the journal Nature.

They named the creature Puijila darwini (“pew-YEE-lah dar-WIN-eye”). That combines an Inuit word for “young sea mammal,” often a seal, with an homage to Charles Darwin. The famed naturalist had written that a land animal “by occasionally hunting for food in shallow water, then in streams or lakes, might at last be converted into an animal so thoroughly aquatic as to brave the open ocean.”

Scientists already knew that pinnipeds evolved from land animals. But the earliest known fossil from that group already had flippers. So Puijila shows an earlier stage of evolution, the researchers said.

Puijila measured about three feet from its snout to the tip of its long tail. It resembled a river otter but had a short snout, large eyes and a thinner tail, Rybczynski said. It could hunt on land or in water, where it was apparently “a pretty darned good swimmer,” she said.

The fossil was discovered in sediments of what had been a lake when the Arctic was much warmer, showing Puijila was at home in fresh water as well as on land. Besides eating fish, it probably ate rodents and ducks with dog-like teeth set in powerful jaws, Rybczynski said.

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