A new species of hammerhead shark has been discovered by a team of scientists from the University of South Carolina, according to a report in Science Daily.
The team leader, ichthyologist Joe Quattro, described finding this rare hammerhead in an article in the journal Zootaxa. The reason that it had long eluded discovery is because it is outwardly indistinguishable from the common scalloped hammerhead.
Quattro, a biology professor in USC’s College of Arts and Sciences, didn’t set out to discover a new species, let alone one that exists exclusively in saltwater. A driving force in his scientific curiosity is a desire to better understand evolution.
Beginning with the pygmy sunfish, Quattro and colleagues examined the genetic makeup of fish species within the ancient freshwater drainage systems.
They found the banded pygmy sunfish in all the South Carolina rivers. But two species are much rarer. The bluebarred pygmy sunfish is found only in the Savannah and Edisto systems. The Carolina pygmy sunfish is found only in the Santee and Pee Dee systems. Both species coexist, but they are found nowhere else in the world.
Quattro continued his research by slowly moving down the river systems to the ocean, collecting genetic data the whole way down. In the freshwater rivers, he has examined pygmy sunfishes, other sunfishes and basses. Closer to the sea, he has looked at shark pups.
The hammerhead is one of a number of species of shark which use South Carolina is a pupping ground. The female hammerhead births her young at the ocean-side fringes of the estuary; the pups remain there for about a year to enable them to grow before moving out to the ocean to complete their life cycle.
After careful study and research, which is fully described in Zootaxa, the new species of hammerhead shark was identified as having 10 fewer vertebrae – and this is the defining morphological difference.
Although deriving great satisfaction from discovering a new type of hammerhead shark, Quattro has not stopped in his quest to delve further into this field. He has established locations and genetic signatures for a number of closely related, yet distinct, species in South Carolina’s rivers, estuaries and coastal waters.
To appreciate the rarity of the discovery, Quatrro has pointed out that “Outside of South Carolina, we’ve only seen five tissue samples of the cryptic species… And that’s out of three or four hundred specimens.”
Shark populations have greatly diminished over the past few decades. and the hammerhead shark is no exception.Quattro says, “The biomass of scalloped hammerheads off the coast of the eastern U.S. is less than 10 percent of what it was historically.”
Quattro said. “Here, we’re showing that the scalloped hammerheads are actually two things. Since the cryptic (new) species is much rarer than the lewini (traditional), God only knows what its population levels have dropped to.”
http://www.inquisitr.com/hammerhead-shark
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