Monday, December 31, 2012

The Last of the Cetotheres?

Researchers have discovered that a type of whale so rare it was thought to have been extinct for 2 million years still lives.

The whale itself — the pygmy right whale — has been spotted a few dozen times. But until recently, it was thought to belong to a different, living whale family. It was only recently that scientists discovered the whale belonged to a family they once thought extinct.

The findings, published last week in the Proceedings of the Royal Society B, help explain why the pygmy right whale looks so different than other whales: it's the last living relative of an ancient species long thought extinct. The living pygmy right whale is, if you like, a remnant, almost like a living fossil, the last survivor of quite an ancient lineage that until now no one thought was around.

Based on physical evidence, the whale was thought in the past to have descended from baleen whales between 17 million and 25 million years ago. Upon studying the creatures' physical characteristics though, researchers at the University of Otago concluded that the whales are more likely to have descended from a whale family that includes the bowhead whale.

The pygmy right whale's snout is arched and frownlike, making it different from most living whales. The research team studied skull bones and other fossil fragments, ultimately coming to the conclusion that the whale was descended from a family of whales called cetotheres, which were thought to have gone extinct about 2 million years ago.   The findings are the first step toward reconstructing ancient lineage back to the point when groups first split off.

Image credit: University of Otago