Scientists identified a new species of Australian humpback dolphin with the scientific name Sousa Sahulensis. The Australian humpback dolphins are a widespread group of coastal cetaceans ranging from the coast of West Africa to the northern coast of Australia.
The authors of the study were Thomas A. Jefferson of Clymene Enterprises and Howard C. Rosenbaum of the Wildlife Conservation Society. The study of WCS was published on 1 August 2014 in the online edition of the journal Marine Mammal Science.
The scientific name Sousa Sahulensis is derived from the Sahul Shelf. Sahul shelf is an underwater shelf stretching between northern Australia and southern New Guinea, where the Australian humpback dolphin occurs.
The species found is one of four recognised species of humpback dolphin. The other three closely related species are:
• The Atlantic humpback dolphin (Sousa teuszii)
• The Indo-Pacific humpback dolphin (Sousa chinensis) found in South-East Asia and the Chinese coast
• The Indian Ocean humpback dolphin (Sousa plumbea)
Characteristics of Australian humpback dolphin
• It is gray in colour and has a characteristic cape pattern on its back. The new species looks markedly different from its nearest relative. The Indo-pacific humpback is white with a pink tinge whereas the new species is dark grey with a distinctive dark cape. It also has a lower dorsal fin.
• There is currently no population estimate for the Australian humpback dolphin, but based on the estimates, it is unlikely that more than a few thousand dolphins of that species exist.
• The new species found is already under the threat of extinction. The species is enlisted in IUCN red list under the category of Near Threatened.
• The humpbacks species are in danger from fishing, being hit by ships, vessel collisions and coastal development.
• Efforts to protect humpback dolphins and other coastal dolphins, and their most important habitats are essential for the survival of these species.
The new study, examining a taxonomically confused group of marine mammals, contains detailed reviews and descriptions of the currently recognised four humpback dolphin species, using external and skeletal measurements, colouration, molecular genetics, and geographic distribution.
The study is the next step building upon recent studies that first detected the existence of a unique humpback dolphin species inhabiting the waters of northern Australia and the island of New Guinea, using genetics and morphological characters.
Another interesting finding of the study was the existence of Wallace Line as a barrier for marine species and the divide between Indo-Pacific and the Australian humpback dolphins seems to coincide with this border.
Wallace Line was given by Alfred Russell Wallace, one of the first naturalists to examine in detail the life of the Malay Archipelago. To the west of the line, terrestrial animal species are mostly of Asian origin and to the east; animal species largely descend from Australasian ancestors.