Fossils in a lump of rock recovered by University of Otago paleontologists 30 years ago have brought them closer to finding the common ancestor of modern right and minke whales.
The researchers are rewriting the history of New Zealand’s ancient whales by describing a previously unknown genus of baleen whale, which lived more than 27.5 million years ago.
The rock was found in the Hakataramea Valley, in South Canterbury.
"It’s been great seeing this come out," Prof Ewan Fordyce, of the Otago geology department, said about the discovery, the latest in a series of ancient finds uncovered through the department.
"It’s always thrilling to bring a project to the end."
The new genus and species of extinct baleen whale is based on a skull and associated bones unearthed from the Kokoamu Greensand.
This is a fossil-bearing rock unit in the South Canterbury and Waitaki district from the Oligocene period (33.9 million to 23 million years ago). A former PhD student in the Otago department, Dr Cheng-Hsiu Tsai, and his supervisor, Prof Fordyce, have named the new genus Toipahautea waitaki, which translates from Maori as a baleen-origin whale from the Waitaki region.
"It’s about as old a common ancestor as we have for the living baleen whales like the minke whales and the right whales," Prof Fordyce said.
The new genus was "a pretty old whale" from almost half-way back to the age of the dinosaurs, about 66 million years ago.
The latest discovery was about two million years older than the previous oldest-known common ancestor of the two modern baleen whale species.
He believed the oldest ancestor — yet-to-be-discovered — would be about two million years older than the Toipahautea waitaki find, and was likely to be a hybrid, with both teeth and the baleen plates used for filter feeding.
The latest fossils were found in a 200kg block of rock, in January 1988, during a burst of field retrieval work funded by a National Geographic Society grant.
But it was only worked up in recent years with Dr Tsai, who undertook doctoral thesis work on the find and now works at the National Taiwan University, in Taiwan.
The research paper announcing the new archaic baleen whale was published yesterday in scientific journal Royal Society Open Science.