October 30, 2013
New Humpback Dolphin Species Found Off Northern Australia
[ Watch the Video: There's A New Dolphin In The Family ]
April Flowers for redOrbit.com - Your Universe OnlineA team of researchers, led by the Wildlife Conservation Society (WCS) and the American Museum of Natural History, have discovered a previously unknown species of humpback dolphin swimming off the coast of northern Australia.
The research team used both physical features and genetic data to study the evolutionary history of this family of marine mammals in order to determine the number of distinct species in the family of humpback dolphins, which are named for a peculiar hump just below the dorsal fin. The Atlantic humpback dolphin is a previously recognized species. The current study, however, provides the best evidence to date that the Indo-Pacific humpback dolphin is split into three species - one of which was previously unrecognized by the science community.
"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. "This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species."
The research team proposes that at least four species in the humpback dolphin family be recognized: the Atlantic humpback dolphin (Sousa teuszii), which inhabits 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 which has yet to be named. Naming species is a formal process that occurs through a separate and complementary process based on the scientific findings.
"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.
The research team assembled a large collection of physical data to bring taxonomic clarity to a widespread, yet poorly understood, group of dolphins. The physical data was gathered mostly from beached dolphins and museum specimens. The team examined features from 180 skulls covering most of the distribution area of the group in order to compare morphological characters across this region. They also collected 235 tissue samples from animals in the same regions, which stretched from the eastern Atlantic to the western Pacific Oceans - analyzing both mitochondrial and nuclear DNA for significant variations between populations.