Arctic fossil is “missing link” to seals

By Randy Boswell, Vancouver Sun – April 23, 2009

A Canadian-led team of scientists working on a remote Arctic island has discovered the fossilized remains of an extinct forerunner of the modern seal—a stunning new species hailed as the “missing link” in land-to-sea evolution predicted by Charles Darwin.

The 20-million-year-old creature, unearthed on Nunavut’s Devon Island, was about one metre in length and possessed otter-like limbs and tail but the skull and jaw structure of a pinniped—the diverse family of marine mammals that includes members such as seals, sea lions and walruses.

Unveiled in the latest issue of Nature, the ancient animal is described as a semi-aquatic meat-eater with webbed feet adapted for speedy swimming, but also possessing nimble legs for hunting on land.

The discovery team—which is headed by Canadian Museum of Nature paleontologist Natalia Rybczynski and has also included the renowned, 77-year-old American scientist Mary Dawson—has labelled the find Puijila darwini: an Inuktitut word meaning “young sea mammal” followed by a Latinate tribute to Darwin.

The great British naturalist has been the focus of international celebrations this year to mark the 200th anniversary of his birth and the 150th anniversary of his landmark treatise on evolution, On the Origin of Species.

Darwin foretold the discovery of a transitional carnivore such as Puijila that would bridge the gap between land mammals with feet and marine mammals with flippers.

“A strictly terrestrial animal,” he wrote in the 1860s, “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.”

Darwin observed: “We may believe that the progenitor of the seal did not possess a flipper, but a foot with five toes fitted for walking or grasping.”

Rybczynski said it appears Puijila lived in a freshwater habitat—fresh evidence to challenge the prevailing theory that pinnipeds moved directly from land to ocean to exploit saltwater prey.