Tuesday 3 April 2012

An Ancient Ancestor To Arctic Whales

The 3 to 4 million year old skull of Bohaskaia monodontoides,
 an ancient species of beluga whale
In 1969, humans landed on the Moon. Richard Nixon became president of the United States, and Elvis was known as 'the King.'

On a  less cultural note, workers in a mine near Hampton, Virginia, USA found a bizarre fossilised skull. It was taken to the Smithsonian Museum in Washington DC, but like so many specimens, was simply stored away in the back rooms and given no further attention whatsoever.

An artist's impression of Bohaskaia monodontoides (foreground).
 Its descendants, the beluga whale and the narwhal are in
the background
It was only in late 2010, that Jorge Velez Juarbe from Howard University in Washington, re-examined the remains. When the skull was first discovered, it was loosely identified as coming from a species of beluga whale. Juarbe's research shows its true importance. 

'We realized this skull was not something assignable to a beluga, and when we sat down, comparing the fossil side by side with the actual skulls of belugas and narwhals, we found it was a very different animal' said study researcher Nicholas Pyenson, of the Smithsonian's National Museum of Natural History.

It was given the name of Bohaskaia monodontoides and dated to around 3 to 4 million years old, making it a mid Pliocene creature. Analysis of the geological layer which it came from shows this creature lived in warm shallow water. The researchers are still unsure why their modern descendants, namely the beluga whale and the narwhal, strayed into the cooler, deeper waters of the Arctic circle. Their bodily features show that they are adapted to their environment, with horns and blunt edges designed to break through ice.

One of their hypotheses is that these bizarre marine mammals moved north in order to adapt with changing food sources, which resulted because of climate change and the arrival of the ice age. 'If your food moved North, you'd probably move North, too,' he said.Velez Juarbe will look for adaptions to cold and ice manipulation in the more recent fossil record to consolidate his hypothesis.