Shock over whale find

Scientists are in a state of ‘‘whale shock’’ after discovering that a whale endemic to the southern hemisphere also lived north of the equator.

Pygmy right whales, one of the smallest baleen whales, were thought to have existed nowhere else in the world. It was known as a ‘‘southern hemisphere specialist’’, native to the southern waters off Australia, South America, Africa and New Zealand.

But research of a fossilised skull found in Japan after World War II, as well as a more recent discovery of a fossilised ear bone found in Italy, has blown what scientists knew about this marine mammal out of the Southern Ocean.

‘‘This is a shocking discovery which really upsets everything we thought we knew about the history of what is really the alien amongst all living whales,’’ senior curator of vertebrate palaeontology at Museums Victoria, Dr Erich Fitzgerald, said.

The Japan fossil was found at a limestone quarry on the island of Okinawa by US geologists. It remained out of sight for years in a cabinet at the Smithsonian Institution, Washington DC.

Fitzgerald studied it while working there in 2008 as a research fellow.

‘‘I looked at the label with it and saw it was actually from, of all places, Japan and my jaw dropped – I couldn’t believe it.’’

The ear bone, found ‘‘in the past couple of years’’, left Fitzgerald and colleagues in no doubt.

‘‘Our Italy colleagues suspected it was a pygmy right whale but it was only after they sent photos to my co-author Dr Felix Marx that we said that’s also a pygmy right whale.’’

In 2012, Marx, as a PhD student at the University of Otago, determined that the pygmy right whale was the last surviving species cetotheres – a once diverse family of baleen whales – thought to have become extinct around two million years ago.

This latest research was published in science journal, Current Biology, yesterday.

The whale’s existence in the northern hemisphere is likely due to climate change.

The warm, tropical waters at the equator acts as an ‘‘invisible barrier’’ to marine mammal migration as it lacks food.

‘‘When global climate cools dramatically there are these pulses of production of food,’’ Fitzgerald said. ‘‘The water is colder and they can move right up to the equator and indeed, just every now and then, populations might cross that boundary and we think that’s what the pygmy right whale did.

‘‘Then, when conditions warm again and the equator becomes this barrier to whales and other marine megafauna, those populations get separated and what’s probably happened is the pygmy right whale got separated.

‘‘Through random events, the vagaries of evolution, changes in local environment, they just didn’t make it through to the present but they did survive in the southern oceans.’’

Fitzgerald, speaking from a CAVEPS conference at Queenstown, said the discovery was the equivalent of fossilised kangaroo bones being discovered in Times Square, New York, or polar bear bones being found on the Chatham Islands.

‘‘Until the discovery of these two fossils, both in the northern hemisphere, one in the Pacific Ocean, one in the Mediterranean Sea of all places, there was no hint, no sniff of this major group, this mysterious group of baleen whales.’’