COLUMBIA - A new, genetically distinct species of hammerhead shark, the ninth recognized species of hammerhead, has been discovered off the South Carolina coast.
The new species appears to be rare. Classified under the genus sphyrna, it will be called the "cryptic species" for now.
Joe Quattro, a biology professor at the University of South Carolina, worked with Jim Grady of the University of New Orleans and Trey Driggers of the National Marine Fisheries Service in making the find.
Mr. Quattro discovered the new species while studying along the coast with biologists from the South Carolina Department of Natural Resources.
Mr. Quattro and his colleagues found that genes in the mitochondrial DNA - the DNA passed from mothers to their offspring - differed significantly among sharks that were classified as scalloped hammerhead sharks.
The studies also revealed that another independent genetic marker differed substantially between the two groups of scalloped hammerheads.
"This cryptic shark was genetically distinct," said Mr. Quattro, whose research was published recently in the journal Marine Biology.
Scalloped hammerheads are common along the coast and sharks of the cryptic species were found from Florida to North Carolina. The newborn cryptic sharks, however, were found mainly along the South Carolina coast.
"The apparent abundance of the cryptic species in coastal South Carolina could be a result of sampling, but it might also highlight the fact that the South Carolina bays are the more important nursery grounds for the cryptic species," Quattro said.
Something as simple as the salinity of the water might explain why the sharks prefer the South Carolina coast, said Mr. Quattro, who plans a field trip this summer to tag the cryptic sharks so scientists can learn more about them.
Because they seem to have a narrow geographic distribution, the sharks may be at greater risk for extinction.
"If South Carolina's waters are the primary nursery grounds for the cryptic species and females gather here to reproduce, these areas should be conservation priorities," Mr. Quattro said.