According to a news release from the University of South Carolina, a new species of hammerhead shark has been discovered. Ichthyologist Joe Quattro and his colleagues recently detailed an uncommon shark, the Carolina hammerhead, that had long escaped finding due to its similar appearance to the common scalloped hammerhead. The new species, Sphyrna gilberti, highlights the frailty of shark diversity due to ongoing human predation.

Quattro and his colleagues weren’t trying to find a new hammerhead shark species. In fact, Quattro was mostly concentrated on fish in the freshwater rivers that move through the state before exiting into the western Atlantic Ocean.

The Palmetto State is a well-known pupping ground for several species of shark, including the hammerhead. The female hammerhead will give birth to her babies at the ocean-side edges of the estuary; her young stay there for a year so, developing, before swimming out to the ocean to finish their life cycle.

As they examined the hammerheads, Quattro and his colleagues discovered an abnormality. The scalloped hammerheads that they were gathering had two varying genetic signatures, in both the mitochondria and nuclear genomes. They discovered that a curator of the Florida Museum of Natural History had detailed an anomalous scalloped hammerhead in 1967 that had 10 fewer vertebrae than Sphyrna lewini. The team analyzed the sample and determined that it made up a cryptic species (a species that is physically almost identical to the more common species).

Quattro’s research reveals the rarity of the new hammerhead shark species.

“Outside of South Carolina, we’ve only seen five tissue samples of the cryptic species,” Quattro said. “And that’s out of three or four hundred specimens.”

The study’s findings are discussed in greater detail in the journal Zootaxa.