A New Dolphin Species?

Nearly 10 years of research regarding coastal dolphins that call the shoreline and estuaries of the eastern Atlantic Ocean home, from New York state to Florida, has resulted in the discovery of a new species. These nearshore bottlenose dolphins have always been thought to share the same type of genetics as those that stay offshore. However, analysis of DNA plus tissue samples, skull structure, and vertebrate columns collected from stranded and deceased dolphins along the eastern shoreline has indicated that there is a difference.

Several scientists working with NOAA for nearly a decade have concluded that there are now two separate species of bottlenose dolphins. Common bottlenose dolphins, both offshore and along the coastline, were scientifically named Tursiops truncatus for more than 16 decades. The new species has been scientifically named Tursiops erebennus, now commonly known as Tamanend’s bottlenose dolphins, a name derived from the chief of the Nanticoke Lenni-Lenape Indian tribe of New Jersey, where the original specimen of this new species was first identified.

Tursiops erebennus was actually identified back in 1865 by Edward Cope when he noted the coastal dolphins were smaller in size and had fewer ribs and fewer vertebrae. However, t. Erebennus and T. Truncatus subsequently became synonymous as one species.

Because of evolutionary differences and DNA studies, the two species are now being identified as different. Further research indicates that these coastal bottlenose dolphins on the east coast from New York to New Jersey are more closely related, genetically, to the bottlenose dolphins in the Gulf of Mexico and the Caribbean Sea. 

The 10,000 Islands Dolphin Study Project team consistently points out to guests that the coastal, bay, and estuarine bottlenose dolphins are smaller than the offshore, primarily because of habitat. Coastal varieties do not need big muscles to dive deep, nor do they need huge lungs since the waters are so shallow, which naturally limits water depth.

The team has consistently referred to our Marco Island population as Tursiops truncatus. Still, it may have to consider that our population is more closely related to the newly rediscovered erebennus species. Additional studies are ongoing to clarify where our local dolphins belong scientifically. Stay tuned for more details as they develop.

As a safety note, this new name does not change the protective status of these dolphins under the Marine Mammal Protection Act. All dolphins within United States territorial waters will receive maximum protection under the law.

Bob is the lead Naturalist for the team on board the dolphin study vessel Dolphin Explorer. He is the author of two books and twice a national award-winning columnist for Coastal Breeze News. He is a regular speaker at area venues and reports the team’s documentation to institutions worldwide. Bob loves his wife very much!