Ancient NZ whale, new discovery
A new species of whale found in a South Island quarry is the oldest known ‘‘true’’ baleen whale in the world and its skull is estimated to have been almost as long as a person is tall.
Toipahautea waitaki is estimated to have lived about 27.5 million years ago, but a fossil of the whale was recovered from a working quarry in the Hakataramea Valley of South Canterbury in 1988.
However, it was only worked on recently. Now, New Zealand and Taiwanese researchers have identified the fossil as a new genus and species of whale.
When the fossil was uncovered, researchers found a range of separated but associated bones including a partial skull, the lower jaw, vertebrae, two scapulae, a partial humerus and ribs.
From the existing fossil bones the estimated skull length was 1.5 to 1.6 metres long and the body was estimated to be about 5m long. By whale standards, that was on the small side.
Examination of the fossil suggested the specimen was a physically immature individual, either juvenile or sub-adult age.
The jaw structure was consistent with baleen-assisted gulpfeeding, researchers said.
Baleen whales are a group of Mysticeti, large whales usually from colder waters that lack teeth but have baleen plates in the upper jaw which are used to filter food such as krill out of large quantities of seawater.
A paper describing the whale said: ‘‘The origin of baleen and microphagous feeding by cetaceans marks a major evolutionary breakthrough, leading ultimately to the emergence of the largest animal, the blue whale.’’
The University of Otago’s Professor Ewan Fordyce said the discovery was significant in New Zealand’s fossil history.
‘‘This is a pretty old whale that goes almost half-way back to the age of the dinosaurs. We are tracking whale history back through time.
‘‘This newly-named whale [is] about as old a common ancestor as we have for the living baleen whales like the minke whales and the right whales.’’
Fordyce expected the ancient whales’ history books may keep being rewritten in years to come.
‘‘We are pretty sure there are some species [of baleen whale] that will be older than these. But right now it anchors the modern baleen whale lineage to at least 27.5 million years.’’
Fordyce and his former student, Dr Cheng-Hsiu Tsai, named the whale. In Ma¯ori, it means ‘‘a baleen-origin whale from the Waitaki region’’.
The researchers were not able to determine how the whale died.
Fordyce said it could have been attacked by a shark, stranded on a beach or died of disease.
When it died, it sank to the bottom of the sea floor with its skeleton falling apart and becoming a hub for coral and other organisms to grow on.
A paper describing the whale was published on Wednesday in the scientific journal Royal Society Open Science.
Baleen whales are a group of Mysticeti, large whales usually from colder waters that lack teeth. Here’s a cast of a primitive baleen whale Tokarahia. (FILE PHOTO)