They were hiding in plain sight. Where once there was one species of humpback dolphin roaming the Indian Ocean, now there are three.
Humpback dolphins (dolphins of the Sousa genus) live around the coasts of Africa, south Asia and Australia. They are named for a small hump just in front of their dorsal fin.
It has always been difficult to determine how many humpback dolphin species there are. Many biologists think there are just two: the Atlantic (Sousa teuszii ) and Indo-Pacific (Sousa chinensis ) – but others think the Indo-Pacific dolphins are divided into two species.
To try and settle the question, Martin Mendez of the American Museum of Natural History in New York and colleagues extracted genetic material from 235 dolphins from across the animals' range and examined 180 dolphin heads.
They found that the Indo-Pacific dolphins could be considered as three distinct species – the two suspected ones, as well as a new as-yet-unnamed species off northern Australia.
This finding reveals that the Indo-Pacific humpback dolphin population is more vulnerable to extinction than ever. What was once considered to be a large population spanning the entire Indian Ocean and beyond is actually three much smaller populations.
Journal reference: Molecular Ecology, DOI: 10.1111/mec.12535
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