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Hello, it's a new species of Pacific iguana

A new species of Pacific iguana has been uncovered by Australian and US researchers, but already its future is looking grim.

In a paper published online in the Philosophical Transactions of the Royal Society B, the team shows there are three living species of Brachylophus iguanas, not two as indicated in current taxonomy.

The new species is named Brachylophus bulabula after the Fijian word for hello.

"In the reptile world the Fijian iguanas are iconic," says lead author Associate Professor Scott Keogh, of the Australian National University's School of Botany and Zoology.

"To discover a new species of them is very exciting."

But he says the new species and its cousins are under threat from habitat loss and attacks by feral cats and mongooses.

Already extinct

Two species of the iguana are already extinct, having been eaten out of existence about 2800 years ago by the earliest arrivals on the island, Keogh says.

He says of the surviving three species, the B. vitiensis,, or Fiji crested iguana, is listed as critically endangered and the other two as status unknown, due to lack of information about their numbers.

The new species was uncovered after analysis of the mitochondrial DNA of 61 iguanas from 13 islands.

The study shows the B. bulabula iguana is genetically and physically different from the two other species.

It has a different coloured nose, is intermediate in size, has a slightly different pattern on its body and is found only in the central region of Fiji.

As part of the research the team also evaluated competing arguments about how the iguana arrived in the Pacific.

He says the Pacific iguanas of the Fijian and Tongan archipelagos are a bio-geographic enigma because their closest relatives are found only in the Americas.

'Floated on some kind of raft'

Keogh says the genetic analysis adds weight to the theory the iguanas "floated on some kind of raft" to the Fijian islands somewhere between 13 to 14 million years ago.

The competing argument suggests the animals came via Asia when Fiji was connected to Melanesia.

"The problem with that is it requires there to be relatives in Asia and there aren't," he says.

The analysis also shows that with only one exception, every island for which there were samples was represented by at least one distinct iguana lineage.

Keogh says their work is particularly important in helping the Fijian Government find ways to protect the reptile.

The largest grouping of the rare reptiles is found on Yadua Taba, the official reserve for the crested iguana, where some 10,000 iguanas are believed to live.