DNA samples reveal new dolphin species in Australian waters

Two north Queensland researchers have identified a new species of dolphin in Australian waters. The australian snubfin dolphin lives in shallow coastal waters in northern Australia and possibly Papua New Guinea.

It initially was thought to have been an irrawady dolphin, usually found in Asia and Australia.

But researcher Isabel Beasley, a PhD student from Townsville's James Cook University, says DNA samples and skull measurements have proved otherwise.

"The australian snubfin has three colours, whereas the Asian dolphin has just uniform slate grey colour with a white belly," she said.

"The other differences are in the dorsal fin height and flipper shapes. Also within the skulls, there's a lot of differences in the skulls."

It is the first discovery of a new dolphin species in more than 50 years.

Ms Beasley says the snubfin has a smaller fin compared with most other species.

Dugong confusion
The species is often confused with a dugong.

"The way that its forehead is shaped, it's very rounded and many people do confuse the two," Ms Beasley said. "But it is that small little dorsal fin on the back of its body [is] how you can distinguish it."

She says it is a very shy dolphin, tending to keep away from boats, unlike more showy bottlenose and other species of dolphin.

Ms Beasley has been studying the Asian irrawaddy dolphin since 1996.

That species is in trouble: Khmer Rouge guerillas hunted irrawaddy in the Mekong River in the early 1970s and they are still considered a delicacy in that area.

Three years ago, Ms Beasley was invited into Townsville-area dolphin investigations.

"I met a man at the Museum at Tropical Queensland, Dr Peter Arnold, and him and a man called George Heinsohn who also worked at James Cook University had been actually also been studying this population since the 1960s and 1970s," she said.

"They'd written a paper in 1996 where they had come to the conclusion that there may be differences.

"So we worked together from that point on, from about 1999 onwards, Peter Arnold, myself and George Heinsohn and that's when we came to the conclusion that there were so many different characters that there was potential for species-level differences."

DNA profiling
With subtle physical differences between the Asian and Australian dolphin confirmed, Ms Beasley was left to get DNA profiling to settle the matter.

"A new species of mammal occurs very, very rarely - in terms of dolphins the last dolphin species was discovered back in 1956," she said.

"There's not many countries in the world that have their own particular species and although it looks like ... it may also occur in PNG waters - the majority of the population appears in Australia.

"So it's extremely important in terms of conservation and management that Australia now focuses very strongly on this new species."

Not much is known about Australian snubfin dolphin numbers but about 200 have been observed in the Townsville area.

Like other dolphins, they are susceptible to shark nets, coastal development and harassment from fishing and tourist boats.

The new dolphin species will be named after George Heinsohn.

Dr Heinsohn examined carcasses of dolphins that were stranded or caught in shark nets in the late 1960s and 1970s. These specimens contributed valuable information used to designate the new species.

Source: www.abc.net.au