![A team at the University of South Carolina has discovered a new species of hammerhead shark. While finding new species is not all that rare, […]](/wp-content/uploads/2013/02/NEWSICON2-620x300.png "Cryptic hammerhead shark species discovered")
A team at the University of South Carolina has discovered a new species of hammerhead shark. While finding new species is not all that rare, a find as large as this is, especially as it was discovered in the well studied waters of South Carolina. The outward features of this shark make it indistinguishable from those of the common scalloped hammerhead shark Sphyrna lewini allowing this cryptic species has remained undetected for so long.
South Carolina’s estuaries are well known pupping areas for several species of shark, including the common scalloped hammerhead. They give birth to their young at the ocean side fringes of the estuaries where pups remain for a year to mature before moving to the oceans to complete their lifecycle. The team, while collecting genetic data on the makeup of fish species in South Carolina’s ancient freshwater rivers and estuaries, found two different genetic signatures in the scalloped hammerheads in both the mitochondrial and nuclear genomes. Identification of this cryptic species is supported by an observation made by renowned curator of Florida’s Natural History museum Carter Gilbert in 1967. He described a specimen of S. lewini with fewer than 10 vertebrae. It is now known that this difference in vertebrae is the only defining and distinguishable morphological feature of this species.
After initially publishing preliminary evidence for the existence of this cryptic species in 2006, the team, led by ichthyologist Joe Quattro, continued to collect data to fully describe the new species S. gilbertis; named in honour of the first individual to describe it.
The new species is very rare outside South Carolina and only five tissue samples of the cryptic species have been found. This emphasises the fragility of shark diversity in the face of human predation. Shark populations have diminished in recent decades, the biomass of scalloped hammerheads off the coast of the US being less than 10% of that recorded historically The discovery of this cryptic species, as Quattro explains, does not help paint a better picture “Since the cryptic species is much rarer than the lewini, God only knows what its population levels have dropped to.”
Read more at : http://biotaxa.org/Zootaxa/article/view/zootaxa.3702.2.5?utm_source=shark_story_test&utm_medium=editorial&utm_campaign=footer_link
