The discovery of a new species of hammerhead shark may sound like bad news for swimmers. But shark bites are rare, and it turns out this may be worse news for sharks.

The shark, as yet unnamed, closely resembles the scalloped hammerhead shark, a species currently up for protection as an endangered species due to the high commercial demand for its fins.

The existence of this new species, originally noticed off the southeastern United States in 2005 and now confirmed as a wide-ranging oceanic shark, shows that the scalloped hammerhead may be in even worse trouble than originally thought, since many sharks counted as scalloped hammerheads were presumably the look-alike species. And the discovery suggests that the new hammerhead species may be facing extinction even before it has a name.

“It’s very important to officially recognize, name and learn more about this new hammerhead species and the condition of its populations through systematic surveys,” said Mahmood Shivji, who oversaw the new research at the Nova Southeastern University Oceanographic Center’s Save Our Seas Shark Center USA and Guy Harvey Research Institute, in a news release. “Without management intervention to curtail its inadvertent killing, we run the risk that overfishing could eradicate an entire shark species before its existence is even properly acknowledged.”

The shark was originally discovered off the South Florida coast in 2005, as Shivji and his team conducted agenetic analysis of what they thought were scalloped hammerheads. A separate team from the University of South Carolina found specimens off that state's waters. At the time, there was some question over what to make of these discoveries. But in a study published in the latest edition of the journal Marine Biology, Shivji and six colleagues from other universities and organizations, say they have found the shark off the coast of southernBrazil, site of busy commercial hammerhead fishery.

Danillo Pinhal, then a visiting graduate student at Nova, had done the lab work while researching scalloped hammerheads off Brazil, finding that his genetic identification tests weren't working on some samples.

"The finding of this species all the way down in Brazilian waters, where hammerhead sharks are heavily fished, raises concerns about the population status of both species not just in U.S. waters but throughout the western Atlantic," said Pinhal, now assistant professor at the UNESP-São Paulo State University. "It’s an international issue now and it’s essential that further research on this new species be conducted in Brazilian waters.”

The new shark and the scalloped hammerhead split from a common ancestor about 4.5 million years ago, according to the scientists’ genetic analysis. Although they resemble each other, the new species has 20 fewer vertebrae.

“It’s a classic case of long-standing species misidentification that not only casts further uncertainty on the status of the real scalloped hammerhead but also raises concerns about the population status of this new species,” Shivji said.

Maggie Miller, a biologist with the endangered species conservation section of the National Marine Fisheries Service, said the fisheries service will consider the studies on the new shark as it considers whether to add the scalloped hammerhead to the endangered species list. A preliminary decision is expected in August.

Sonja Fordham, president of Shark Advocates International, said the discovery argues for a broader approach to the conservation of sharks in which it's easy to mistake one species for another.

"The news bolsters conservationists' arguments that rules currently being developed under the National Marine Fisheries Service fishery management plan for sharks apply to not just overfished scalloped hammerheads but also similar looking species," she said.

Fins from the various hammerhead species command high prices in China and other East Asian countries because they have long cartilage needles that are prized for shark-fin soup.