Meet Sphyrna gilbert, aka the Carolina hammerhead, the newest member of the hammerhead shark family which has been discovered. It looks practically the same as the scalloped hammerhead, but it is genetically different from it.
The Carolina hammerhead shark also has fewer vertebrae than does the scalloped hammerhead, 10 fewer, according to the latest research on this rare shark species.
According to Joe Quattro, an expert on fish from the University of South Carolina, the Carolina hammerhead is so rare that only “five tissue samples” of it have been discovered anywhere else besides off of the coast of South Carolina.
A study about these sharks was published in the journal Zootaxa. It was a more comprehensive follow-up to a preliminary study on the shark published in 2006.
The Carolina hammerhead uses the estuaries off the shore of the Carolinas to give birth. Its offspring, like those of canines, are called “pups.”
How did Joe Quattro discover the Carolina hammerhead?
Joe Quattro and his team of fellow scientists collected 80 young hammerheads that appeared to be scalloped hammerheads. But, when they analyzed the DNA of the sharks, Quattro and his team realized that 54 of the 80 sharks they’d captured were not scalloped hammerheads, but were an entirely different species of hammerhead shark. The nuclear and mitochondrial genomes of both hammerhead species had genetic signatures that were different from each other.
Besides the different DNA and having fewer vertebrae than scalloped hammerheads, the Carolina hammerheads are also somewhat smaller.
Quattro laments the drastic decline of sharks. The populations of sharks in general have declined by approximately 90 percent in just the last few decades, according to Quattro.
It is difficult to know just how drastically the population of the Carolina hammerheads has dropped and how many are left in the wild, but they are definitely rarer than the scalloped ones.
The desire of the Chinese for shark fin soup is one of the factors that have contributed to the decline of sharks. Just how many sharks are killed to meet the demand for shark fin soup? Nearly 100 million are slaughtered every year for this purpose, but the amount of shark fin soup consumed in China has dropped by around half in just the last two years.
Actually, after Quattro and the other researchers searched through years of scientific literature, they found an account that someone called Carter Gilbert (who was the Florida Museum of Natural History’s curator) had written in 1967 describing a species of hammerhead shark that had been caught off the coast of Carolina that had ten fewer vertebrae than “normal” scalloped hammerheads had.
Gilbert had discovered the new species back then, though he didn’t realize that he had. The shark Gilbert had written about was still at the museum, and after Quattro and company checked it out, they knew it was a Carolina hammerhead. Still, to honor Gilbert, Quattro and his team used his name, calling the shark Sphyrna gilberti.
The Carolina hammerhead is what is known as a “cryptic species.” That’s a species which closely resembles another one, but which is genetically different.
Though it is currently unknown exactly how large the population of Carolina hammerheads is, their numbers are on the decline, as the numbers of all sharks are. With conservation measures, and a program to protect this species, it still might be possible to save it from the brink of extinction.
Written by: Douglas Cobb