New subspecies of bottlenose dolphin identified

New subspecies of bottlenose dolphin identified

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The new subspecies is smaller than the common bottlenose dolphin, and is found only in the eastern tropical Pacific.

A new bottlenose dolphin subspecies has been identified, and it is found only in the eastern tropical Pacific Ocean, according to a study published in the Journal of Mammalian Evolution.

Called the Eastern Tropical Pacific bottlenose dolphin (Tursiops truncatus nuuanu), it is smaller than other common bottlenose dolphins, and is likely to prefer the deep offshore waters between southern Baja California and the Galapagos Islands. 

In the study, the researchers examined the skulls and total body lengths of more than 130 bottlenose dolphin specimens from the eastern Pacific and western North Pacific held in museum collections across the United States. Multivariate and clustering analyses were used to determine the level of differentiation among the bottlenose dolphin populations. 

Significant differences in form were found, thus prompting the researchers to classify the specimens into two distinct clusters. "The bottlenose dolphins found in offshore waters of the eastern tropical Pacific formed one single cluster, and they were significantly smaller—based on skull and body length—than common bottlenose dolphins forming the other cluster," said Ana Costa, a marine researcher with the Rosenstiel School of Marine, Atmospheric, and Earth Science at the University of Miami.

"Our findings indicated that the offshore bottlenose dolphins of the eastern tropical Pacific are speciating from the globally distributed common bottlenose dolphins and should be described as a different subspecies."

The study's findings may have have implications when it comes to the protection of the dolphins.

"By better understanding the biodiversity in the ocean, we can better understand the relationship of the dolphins with their environment and the threats they face, and in this way better define conservation and management strategies," said Costa.

Journal of Mammalian Evolution

Press releases from Divers Alert Network (DAN)