Following the discovery of a ‘Lost world’ full of unknown species in an unexplored Australian rainforest last week, a team of researchers working for the Wildlife Conservation Society, the American Museum of Natural History, and numerous other groups have found a species of humpback dolphin previously unknown to science swimming in the waters off northern Australia.
To determine the number of distinct species in the family of humpback dolphins (animals named for a peculiar hump just below the dorsal fin), the research team examined the evolutionary history of this family of marine mammals using both physical features and genetic data. While the Atlantic humpback dolphin is a recognized species, this work provides the best evidence to date to split the Indo-Pacific humpback dolphin into three species, one of which is completely new to science.
“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 Dr. Martin Mendez, Assistant Director of WCS’s Latin America and the Caribbean Program and lead author of the study which appears in the latest edition of Molecular Ecology. “This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species.”
The authors propose recognition of at least four species in the humpback dolphin family: the Atlantic humpback dolphin (Sousa teuszii), which occurs in the eastern Atlantic off West Africa; the Indo-Pacific humpback dolphin (Sousa plumbea), which ranges from the central to the western Indian Ocean; another species of Indo-Pacific humpback dolphin (Sousa chinensis), which inhabits the eastern Indian and western Pacific Oceans; and a fourth Sousa species found off northern Australia yet to be named.
“New information about distinct species across the entire range of humpback dolphins will increase the number of recognized species, and provides the needed scientific evidence for management decisions aimed at protecting their unique genetic diversity and associated important habitats,” said Dr. Howard Rosenbaum, Director of WCS’s Ocean Giants Program and senior author on the paper.
The humpback dolphin grows up to 8 feet in length and ranges from dark gray to pink and/or white in color. The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian and Pacific oceans to the coasts of Australia. The Atlantic humpback dolphin is considered “Vulnerable” according to the IUCN Red List, whereas the Indo-Pacific dolphin species Sousa chinensis is listed as “Near Threatened.” Humpback dolphins are threatened by habitat loss and fishing activity.
As many species are threatened with extinction, the discoveries of more previously unknown creatures is welcome news, and across the world scientists report that they are finding an average of two new species per week. One of the latest mammal species found includes a "monkey that purrs like a cat, " according to a list compiled by the World Wildlife Fund, which details at least 441 new species of animals discovered over a four year period in the vast Amazonian rainforest. In total, the list comprises 258 plants, 84 fish, 58 amphibians, 22 reptiles, 18 birds and one mammal, and does not include the numerous insects and other invertebrates which have also been identified. Unfortunately, as soon as they have been identified many of these new creatures, such as a Flame Patterned Lizard from the Columbian Rainforest, may have to be placed immediately on the "endangered" list.
"These species form a unique natural heritage that we need to conserve. This means protecting their home — the amazing Amazon rainforest — which is under threat from deforestation and dam development," said Claudio Maretti, Leader of Living Amazon Initiative, WWF.