Marine mammal experts have uncovered a new species of dolphin in Australian waters, challenging existing knowledge about bottlenose dolphin classifications and highlighting the country's marine biodiversity.
The researchers, from Macquarie University and Monash University, used genetic methods to identify the new dolphin species, and have had their findings published in November's edition of the journal Molecular Phylogenetics and Evolution.
Dr Luciana Möller, of the Marine Mammal Research Group and the Molecular Ecology Lab at Macquarie University's Graduate School of the Environment, led a study which found that the coastal bottlenose dolphins from southern Australia should in fact be classified as a new species, rather than considered one of the recognised bottlenose dolphin species.
There are currently two recognised species of bottlenose dolphins and both are found in Australian waters: the common bottlenose dolphin generally found in Australia's offshore waters, and the Indo-Pacific bottlenose dolphin, found in coastal waters.
Dr Möller said that it is difficult to distinguish between some species of bottlenose dolphins using only external body features.
"This group to which bottlenose dolphins belong includes several species that have differentiated relatively recently in evolutionary time and therefore it is difficult to distinguish or understand relationships between them based on morphology alone," she said.
The new coastal bottlenose dolphin will be the second dolphin species found only in Australia. Dr Möller says this discovery has important implications for the species and for marine science in general.
"In the current biodiversity crisis, when we are losing so many animal species, it's very exciting to find out about these unique Australian dolphins," she said.
"They should be given special conservation attention due to their limited distribution to coastal waters of southern Australia. Due to their coastal habitat, these dolphins are also more likely to face threats such as pollution, overfishing and entanglement in nets."
Using DNA analysis, the researchers found that the new species was more closely related to the Fraser's dolphin, which is found mostly in the deep waters of the Pacific Ocean.
Dr Möller said her research team's findings demonstrated how important DNA studies are to uncovering hidden marine diversity.
"It suggests we still have a lot to learn about how many marine species are out there," she said.
New dolphin species revealed by genetic test
Emma Young, New Scientist 23 Nov 08;
A new, third species of bottlenose dolphin has been discovered in the waters off southern Australia. It is only the second new dolphin to be discovered in 50 years.
Luciana Möller of the Marine Mammal Research Group at Macquarie University in Sydney, Australia, and her colleagues were studying populations of what they thought were Indo-Pacific and common bottlenoses in southern waters.
DNA analysis, though, revealed that most the animals living close to the shores of the states of Victoria, South Australia and Tasmania were in fact a new species, belonging to a new genus. "They look very like the Indo-Pacific species, but genetically they're very different," says Möller.
The team has called the new species the Southern Australian bottlenose. It is awaiting a scientific name after a formal description.
The Southern Australian bottlenose dolphin is only the second new dolphin to be discovered in 50 years (Image: Macquarie University)
Based on their genetic analyses, the researchers think it is in fact more closely related to the Fraser's dolphin, which lives in deep waters mostly in the Pacific and Indian Oceans. Möller says that since dolphins diverged only between 5 million and 2 million years ago, different species can look morphologically very similar.
Given the animal's apparent preference for coastal waters subject to pollution, fishing and other potential threats, its status now needs urgent further investigation, she says.
The last new dolphin to be discovered was the Australian snubfin, in 2005. Before that, it was the Fraser's dolphin, in 1956.