Geographic Origins
The Arctic as a Centre of Evolution
Distribution of Early Pinnipeds
Some early lineages in the pinniped family are shown here. The red dashed line shows possible paths taken by a Puijila-like ancestor in its spread out of the Arctic. This dispersal pattern represents a new hypothesis with the Arctic as a centre of pinniped evolution. Large dots mark where fossils of the indicated species have been found. Where there is no dot, many fossils of that family were found (along the coastline).
This polar view of the globe shows the continents as they were during Puijila's time, 24 to 20 million years ago. Note the solid land mass where Canada's Arctic islands appear today. The Bering Strait "land bridge" joined North America and Eurasia.
The location on the globe where the fossil of Puijila darwini was found is almost as significant as what the fossil itself tells us.
The existence of such a primitive form of pinniped in the High Arctic suggests that the ancient Arctic land mass may have been a site of origin for the pinniped lineages that eventually gave rise to the modern forms. (Pinnipeds are the group that today consists of true seals, sea lions and the walrus).
In other words, there would have been a hypothetical ancestral species. It could have originated anywhere. In the Arctic, however, its evolution produced many branches of the pinniped family tree. Puijila represents one such branch. Some branches terminated, while others continued to evolve.
The current state of pinniped evolution is represented by true seals, sea lions and the walrus.
Pinnipeds eventually reached all of the world's oceans, except the Indian Ocean. In North America, sea lions are found along the Pacific coast, and the walrus along northern coastlines of the Arctic Ocean, Pacific Ocean and Hudson's Bay. True seals occur in the Arctic and along the Atlantic and Pacific coasts. Until its extinction a few decades ago, one species of seal even inhabited the coastal waters of Florida and the Caribbean.
