Wellington, Nov 19 (IANS): New Zealand researchers Wednesday said they have identified a previously unknown whale group that lived 27 million to 25 million years ago.

The finding by University of Otago palaeontologists was based on fragments of two fossilised skulls found in a rock formation in the north of the South Island's Otago region, preserved from a time when the continent of Zealandia was mostly under water.

Researcher Robert Boessenecker and professor Ewan Fordyce named the new genus tohoraata, which translates as "dawn whale" in Maori.

The new genus belonged to the toothless filter-feeding family eomysticetidae, and it was the first time members of the family had been identified in the Southern Hemisphere.

It vaguely resembled a minke whale, but was more slender and serpent-like, with a skull about 2 metres long and a total length of eight metres.

"This new species differs from modern baleen whales in having a smaller brain case and a skull that is generally much more primitive, with substantially larger attachments for jaw muscles," Xinhua quoted Boessenecker as saying in a statement

Eomysticetids were the earliest toothless baleen-bearing cetaceans, and in many characteristics were intermediate between toothed baleen whales and modern baleen whales, he said.

"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," he said.