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Tens of millions of starfish-like creatures, known as brittlestars, have colonised a vast underwater mountain, south of New Zealand.

The animals are packed so tightly that scientists have dubbed the seamount "brittlestar city".

The team, from New Zealand's National Institute of Water and Atmospheric Research (Niwa), says it is rare to see such an enormous array of the five-armed creatures.

The scientists recorded life at the Macquarie Ridge for the CenSeam programme, which is funded by the Census of Marine Life.

Footage courtesy of Niwa