Plants and Animals

New Species of Hammerhead Shark Confirmed

November 8, 2013 | by Lisa Winter

Photo credit: University of South Carolina

Good news, lovers of hilariously-shaped fish: the discovery of a new species of hammerhead shark off the coast of South Carolina has been confirmed! While it looks nearly identical to the common scalloped hammerhead, genetic sequencing was used to show it is, in fact, a separate species.

The shark has been named Sphyrna gilberti in honor of Carter Gilbert, the ichthyologist who had unknowingly made the first description of the species in 1967 when he wrote about hammerhead specimens with fewer than the expected number of vertebrae. Unofficially, however, the shark is being called the Carolina hammerhead. It is described in the current issue of Zootaxa

The discovery was made by Dr. Joe Quattro, a professor from the University of South Carolina's Marine Science Program. Finding a hammerhead shark was completely unexpected, as his research interests lie mainly in freshwater river fish. His had been taking genetic samples throughout the length of three South Carolina rivers, when his research team encountered hammerheads in the estuary, where females like to give birth.

In 2006, Quattro had initially published genetic information that first hinted of the discovery of a new species. In the following years, they made measurements and catalogued morphological differences for 54 individuals of the novel shark with 24 samples of S. lewini, the well-known scalloped hammerhead. In addition to the genetic differences, S. gilberti have ten fewer vertebrae than S. lewini. This is the largest morphological difference between the two species and was exactly what Carter Gilbert had encountered nearly 40 years earlier. In light of the evidence, it was confirmed that Quattro and his team had discovered a new species.

Currently, the full range of the Carolina hammerhead is unknown. It is doubtful that they exist in thriving populations, as its doppelganger, the scalloped hammerhead, is currently listed as endangered on the IUCN Red List due to overfishing, both commercially and for sport. 

Tags