Wednesday, October 30, 2013

Humpback dolphins discovered off Australia are new species

Scientists use DNA, other analysis to uncover fourth ‘Sousa’ species; new information will help determine management decisions to protect mammals

photo of yet-to-be named humpback dolphins  photo by Guido Parra
Two mammals from a yet-to-be-named species of humpback dolphins jumping in waters off northern Australia; photo by Guido Parra
A previously unidentified species of humpback dolphin was found in waters off northern Australia, a discovery that will provide scientific evidence for helping to manage and protect the marine mammal considered vulnerable and near threatened, the Wildlife Conservation Society announcedTuesday.
The humpback dolphin is distinguished by a peculiar hump just below the dorsal fin, grows up to 8 feet in length, and ranges in color from dark gray to pink and/or white.
Using physical features and genetic data from 235 tissue samples, researchers examined the evolutionary history of this marine mammal to determine the number of distinct species within its family.
Two humpback dolphins swimming together off northern Australia; photo by Guido Parra
Two humpback dolphins swimming together off northern Australia; photo by Guido Parra
The Atlantic humpback species is already recognized, and now the researchers are suggesting the Indo-Pacific humpback dolphin be divided into three species, one of which is new to science and has yet to be named.
“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. “This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species.”
Mendez told the Washington Post that knowing the distinct species is “essential to an appropriate framework for conservation. You have to absolutely know what you are trying to preserve here.”
The authors of the study published in the journal Molecular Ecology propose the four species be broken down thusly:
Two humpback dolphins; photo from Wikimedia Commons
Two humpback dolphins; photo from Wikimedia Commons
The Atlantic humpback dolphin (Sousa teuszii), found in eastern Atlantic off West Africa.
The Indo-Pacific humpback dolphin (Sousa plumbea), ranging from the central to the western Indian Ocean.
The Indo-Pacific humpback dolphin (Sousa chinensis), inhabiting the eastern Indian and western Pacific oceans.
The Indo-Pacific humpback dolphin (Sousa to be named later), found off northern Australia.
“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.
And clearly, the humpback dolphin family is in need of protecting.
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.

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