Ancient New Zealand Whales Were the First to be Completely Toothless
Paleontologists are rewriting the history of New Zealand's ancient whales. They've discovered a previously unknown genus of fossil baleen whales and two species within it.
The two newly discovered whales lived between 27 to 25 million years ago in New Zealand which, at the time, was completely covered by water. These whales were toothless, and lived by filter-feeding-like the humpback whales of today.
One of the whales, named Tohoraata raekohao, vaguely resembled a minke whale. However, it was more slender and serpent-like and stretched about eight meters in length. In addition, its skull contained a number of holes near its eye sockets and arteries.
"This new species differs from modern baleen whales in having a smaller braincase and a skull that is generally much more primitive, with substantially larger attachments for jaw muscles," said Robert Boessenecker, one of the researchers, in a news release. "The lower jaw retains a very large cavity indicating that its hearing capabilities were similar to archaic whales."
The other whale was actually collected in 1949 and named in 1956. Yet it was misidentified as belonging to the genus Mauicetus. Instead, its name has now been changed to Tohoraata waitakiensis.
"Researchers contend with confusing or surprising fossils in museum collections all the time," said Boessenecker. "Often, the best way to solve these mysteries is to go out and dig up another one, which is what Professor Fordyce and his colleagues did in 1993 when they collected the partial skull of Tohoraata raekohao."
The findings reveal a bit more about the evolutionary history of whales. These are actually the first baleen whales to have been completely toothless, which means that they're the earliest known cetaceans to have fully relied on filter feeding.
The findings are published in the journal Papers in Paleontology.