A 27.5 million-year-old fossil that was discovered on the South Island of New Zealand is now described as one of the oldest known species of baleen whales.

Toipahautea Waitaki

Researchers named the new species Toipahautea waitaki, which roughly translates to "baleen whale from the Waitaki region". The fossil had been found in January 1988 about 30 years ago, but researchers were only able to conduct more in-depth study recently.

The creature lived during the Oligocene epoch about 33.9 million to 23 million years ago when New Zealand was an island archipelago surrounded by shallow waters.

Ewan Fordyce, from the University of Otago's Department of Geology, and colleagues who studied the fossil said that the whale is a relatively old one, hailing back nearly halfway back to the age of the dinosaurs.

Relatively Small Compared With Their Modern Kin

The species was small when compared with modern baleen whales. It measured just 19 feet in length, which is just about half the size of a modern minke whale.

"People look at the fossil record and think the early history of many animals is filled with giants, but not for whales. It's only in recent geological times that whales have achieved really large sizes," said Fordyce.

Baleen Whales

Modern baleen whales are filter-feeding marine giants and include many of the largest known cetaceans such as the humpback, bowhead, and minke whales.

Most of these modern species are feeding specialists. The humpback and blue whales, for instance, are known for gulf-feeding. They take mouthfuls of water and krill before squeezing the water out. Right whales, on the other hand, use skin-feeding. They swim with their mouths open at the surface so they can strain out their prey.

The researchers found that the jaws of the Toipahautea waitaki were long, narrow, and toothless, suggesting that they also fed in similar ways to modern-day whales. Nonetheless, they think that ancient baleen whales such as the Toipahautea were likely generalists that used a number of feeding styles.

"Late Oligocene mysticetes vary considerably in jaw form and kinesis, tooth form and function, and development of baleen, implying a wide range of raptorial, suctorial and filter-feeding behaviour," the researchers wrote in their study, which was published in the journal Royal Society Open Science on April 18.

"We here propose that early mysticetes, when transitioned from toothed to baleen-bearing, were generalists and opportunists instead of specializing in any forms of feeding strategies."

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