New species of ancient whale identified

Researchers have identified a previously unknown genus and species of baleen whale in New Zealand, which dates back to more than 27.5 million years.

Baleen whales are a group of Mysticeti, large whales usually from colder waters that lack teeth but have baleen plates in the upper jaw which are used to filter food such as krill out of large quantities of seawater.

"This is a pretty old whale that goes almost half-way back to the age of the dinosaurs. We are tracking whale history back through time," said Ewan Fordyce, a professor at the University of Otago in New Zealand.

The new species of extinct baleen whale is based on a skull and associated bones unearthed from the Kokoamu Greensand, a noted fossil-bearing rock unit in the South Canterbury and Waitaki district from the Oligocene period.

At this time, New Zealand was an archipelago surrounded by shallow, richly productive seas.

"This newly-named whale lived about 27.5 million years ago. It is about as old a common ancestor as we have for the living baleen whales like the minke whales and the right whales," said Fordyce.

The fossil described in the journal Royal Society Open Science was actually recovered from the Hakataramea Valley in South Canterbury 30 years ago in 1988.

However, it was only worked up in recent years with Cheng-Hsiu Tsai, who is currently working at the National Taiwan University.

While the skeleton of the whale was disarticulated when it was excavated, the bones were closely associated, which gave the palaeontologists plenty of material to work with.

In particular, the highly diagnostic earbones were preserved, helping with identification.

The skull was about one metre long and the body about five metres, which means it was a reasonably small species.

"That is about half the size of an adult minke whale," Fordyce said.