The Atlantic humpback is already a known and recognised species, but the discovery of the latest dolphin species provides the best evidence yet of three different types, including one which is completely new to science, researchers said.
The humpback dolphin with a peculiar hump just below the dorsal fin grows up to 2.5 metre in length and ranges from dark grey to pink and/or white in colour.
Australian humpback dolphins swimming off the coast of northern Australia. Photo: AFP
The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian and Pacific oceans up to the coasts of Australia.
"Based on the findings of our combined morphological and genetic analyses, we can suggest that the humpback dolphin genus includes at least four member species," said the Wildlife Conservation Society's Martin Mendez, lead author of the study.
"This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species," he added.
The findings were published in the latest edition of journal Molecular Ecology. The new species is yet to be named.