Previously Unknown 'Dawn Whale' Discovered

A previously unknown genus referred to as "dawn whale" was just recently discovered after paleontologists from the University of Otago rewrote the history of New Zealand's ancient whales.

According to the research describing the revelation, the new genus Tohoraata, which translates as "Dawn Whale" in Māori, contains two new species of baleen whales. Dating back 25 to 27 million years ago, fossils of these ancient behemoths were preserved in a rock formation near Duntroon in North Otago.

Researchers named the younger of the two newly identified whales Tohoraata raekohao, for its unique skull. It contains a number of holes near its eye sockets for arteries. The fossil animal was likely eight meters in length and somewhat resembled a minke whale, though its body was more slender and serpent-like in shape.

"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. The lower jaw retains a very large cavity indicating that its hearing capabilities were similar to archaic whales," PhD student Robert Boessenecker, who helped identify the new genus with his supervisor Professor Ewan Fordyce, said in a statement.

Meanwhile the older fossil, which researchers had previously found in 1949, experienced a case of mistaken identity. It was believed to belong to the genus Mauicetus, a more advanced type of whale called a "cetothere." However given the recent discovery of this distinct genus, its name has since been changed from Mauicetus waitakiensis to Tohoraata waitakiensis.

The new study goes to show that many species, even previously discovered ones such as these baleen whales, are misunderstood and that scientists still have much to learn going forward.

"Researchers contend with confusing or surprising fossils in museum collections all the time. Often, the best way to solve these mysteries is to go out and dig up another one," noted Boessenecker.

Furthermore, the new genus that the fossils represent belongs to the toothless filter-feeding family Eomysticetidae, which occupy a very important position in the evolutionary tree of cetaceans.

"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," Boessenecker added.

The fossils are described further in the journal Papers in Paleontology.