Correction: Earlier versions of this article, including in the print editor of The Washington Post on Tuesday, misidentified the scientific organization that conducted the study.

The as-of-yet unnamed species of humpback dolphin. (Guido Parra)

Researchers said Tuesday that they have identified a previously unknown species of humpback dolphin living off the coast of Australia, a critical first step in efforts to conserve the dwindling numbers of the marine mammal.

Scientists from the New York-based Wildlife Conservation Society reported in the journal Molecular Ecology that they used genetic testing and physical comparison of the cetaceans to settle a long-running controversy about the number of species that exists.

Divided into two groups — one in the Atlantic Ocean and one found in other parts of the world — the population of humpback dolphins is actually composed of four distinct species, the researchers said. In addition to the newly discovered species, they said, one of the current groups should be divided into two. The species occupy the eastern Atlantic Ocean off West Africa, the central and western Indian Ocean, the eastern Indian and western Pacific oceans, and the waters off the coast of northern Australia.

The new information will help governments and conservation groups create policies tailored to each species, said Howard Rosenbaum, director of the society’s Ocean Giants program.

Knowing the distinct species is “essential to an appropriate framework for conservation,” said Martin Mendez, assistant director of the society’s Latin America and the Caribbean program. “You have to absolutely know what you are trying to preserve here.”

(Patterson Clark/The Washington Post)

Humpback dolphins are considered “threatened” in some waters and “vulnerable” in other parts of the world.

Some species may be threatened by fishing in coastal waters, while others are more vulnerable to invasion of their habitats, Rosenbaum and Mendez said.

The researchers conducted genetic testing on tissue from 235 dolphins and examined the craniums of 180 more.