Scientists in New Zealand say they've discovered two previously unknown ancient whale species, rewriting the history of marine mammals in the Southern hemisphere.
Dubbed Tohoraata raekohao and Tohoraata waitakiensis, the whales measured about eight feet in length and lived some 27 million to 25 million years ago. They belong to the Eomysticetidae family--the earliest toothless filter-feeders.
The whales are the first eomysticetids to be found outside the U.S. and Japan. That suggests that the animals roamed the Southern seas and were probably distributed worldwide, according to the researchers.
The fossils were found around 40 years apart in a rock formation in the country's North Otago district.
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Illustration of Tohoraata raekohao, a newly identified extinct species of baleen whale.
Eomysticetids fill an important spot in the evolutionary tree of marine mammals, bridging the gap between toothed baleen whales such as the extinct Mammaladon and modern baleens such as the gray whale.
“They are the first baleen whales to have been completely toothless, and are therefore the earliest known cetaceans to have wholly relied upon filter feeding," Robert Boessenecker, a Ph.D. student in the University of Otago's geology department and one of the researchers, said in a written statement.
A study describing the new findings was published online on Nov. 13 in the journal Papers in Palaeontology.