New Dolphin Species Discovered in Big City Harbor

Identified by DNA tests, the new mammals were right under researchers' noses.
A Burrunan dolphin—one of an entirely new species—surfaces near Melbourne, Australia.

An entirely new species of dolphin has been discovered in Australia, and not in some isolated lagoon but in the shadows of skyscrapers, scientists say.

One of only three new dolphin species found since the 1800s, the Burrunan dolphin—named after an Aboriginal phrase that means "large sea fish of the porpoise kind"—is known from only two populations so far, both in the state of Victoria (map).

About a hundred Burrunan dolphins have been found in Port Phillip Bay (map) near Melbourne, Australia's second most populous city. Another 50 are known to frequent the saltwater coastal lakes of the Gippsland region (map), a couple hundred miles or so away.

Dolphin DNA Surprise

It's long been known that distinct dolphin populations roam off southeastern Australia. But now DNA tests have shown that the creatures dolphins are genetically very different from the two recognized bottlenose dolphin species, the common bottlenose dolphin and the Indo-Pacific bottlenose.

The results were so surprising that the team initially thought there was a mistake and reran the tests, said study leader Kate Charlton-Robb, a marine biologist at Australia's Monash University.

"The main focus of the research was to figure out which of the two [known] bottlenose species these guys were," she said.

"But from the [DNA] sequences that we got, it turned out that they were very different from either of the two known species."

The team also examined dolphin skulls, collected and maintained by Australian museums over the last century, and determined that Burrunan dolphins have slight cranial differences that set the species apart.

Finally, the animals just plain look different, Charlton-Robb said.

Compared to the other bottlenoses, Burrunan dolphins have a more curved dorsal fin, a stubbier beak, and a unique "tricoloration"—including dark gray, mid-gray, and white.

(See a new, snub-fin dolphin species found in New Guineau.)

New Dolphin Nearly Discovered a Century Ago

So how did the dolphins escape researchers' notice for so long?

Physical variations in dolphins in southeastern Australia have been reported for decades, though the new study is the first to use multiple lines of evidence to make a strong case for a new species, Charlton-Robb said.

In fact, the Burrunan dolphin was almost discovered in 1915, after a biologist captured and examined two very different dolphins from Australian waters.

Scientists at the time concluded that both the animals were common bottlenose dolphins, and that their differences were due to one being male and the other female. After reviewing the female dolphin's skeleton recently, though, Charlton-Robb's team determined she was a Burrunan.

Because so few of the new dolphin species are known, the Burrunan research team has petitioned the Australian government to list the animals as endangered.

"Given the small size of the population," Charlton-Robb said, "it's really crucial that we make an effort to protect them."

The new dolphin species is formally described online Wednesday in the journal PLoS One.