The Pacific elkhorn coral was found during underwater surveys at Arno atoll, in the Marshall Islands, by coral researcher Dr Zoe Richards of the ARC Centre of Excellence for Coral Reef Studies (CoECRS).

The coral bears a close physical resemblance to the critically endangered and fast-vanishing elkhorn coral, or Acropora palmata, of the Atlantic Ocean.

But genetic analysis has shown it to be a different species.

\”When I first saw it, I was absolutely stunned. The huge colonies – five metres across and nearly two metres high with branches like an elk\’s antlers – were like nothing I\’d seen before in the Pacific Ocean,\” Dr Richards said in a statement.

\”So far I have only found this new population of coral to occur along a small stretch of reef at a single atoll in the Marshalls group.

It grows in relatively shallow water along the exposed reef front and, so far, fewer than 200 colonies are known from that small area

Dr Richards said Pacific elkhorn colonies were by far the largest of all the Acropora colonies seen at Arno Atoll, indicating they were relatively old.

Whether the Pacific elkhorn is an entirely new species or not is subject to scientific debate.

Dr Richards has discovered that in 1898 a scientist described a coral from the island of Rotuma, near Fiji in the South Pacific whose description fits that of the Pacific elkhorn.

\”Unfortunately at this stage, we do not have any genetic material of A. rotumana to confirm whether or not it is the same species as the Pacific Elkhorn.\”

Either way the discovery is good news. Acropora is the dominant genus of reef-building corals.

Leading coral geneticist Professor David Miller, of the CoECRS and James Cook University, said the discovery showed how much was left to learn about remote reefs of the North Pacific.