Despite having evolved some 250 million old age ago , sixgill shark are still some of the most mysterious wight living in the oceans . So knotty are these inscrutable - sea piranha that researchers have only just enter out that there isa new speciesliving in the Atlantic .
Sixgill sharks are unusual among sharks for being the only extant species to have an extra pair of gill slits ( while a few others have yet another pair still ) . The sixgills have long been split into two coinage – the bluntnose sixgill shark ( Hexanchus griseus ) that can live 2,500 meters ( 8,200 feet ) beneath the airfoil and the bigeye sixgill shark ( Hexanchus nakamurai ) that is smaller and tends to last closer to the surface , although still out of the reach of most biologists .
The bigeye sixgill has been base in most major ocean , and until now was look at a single species . But a raw newspaper bring out that the shark that be in the Atlantic Ocean are a dissimilar metal money than those come up in the Amerindic and Pacific Oceans . This newly described Atlantic species has now been calledHexanchus vitulus .
Publishing their piece of work in the journalMarine Biodiversity , the team used genetic science to adjudicate the argumentation of whether or not there were multiple species of the deep - ocean predators . By analyzing 1,310 base pairs of two mitochondrial genes , they were able to sustain that – despite looking almost superposable – the Atlantic universe was indeed different enough to be elevated to species level .
“ We showed that the sixgills in the Atlantic are actually very different from the ones in the Amerind and Pacific Oceans on a molecular stage , to the breaker point where it is obvious that they ’re a different species even though they look very similar to the naked eye , ” explains Toby Daly - Engel , who co - author the paper describing the new species , in astatement .
This is important because even though little is have a go at it about the sharks or even the thick abysm in which they live , fishing vas are more and more probing the depths in the search of raw caudex .
“ Because we now know there are two unequaled species , we have a sense of the overall variation in populations of sixgills,”saysDaly - Engel . “ We sympathise that if we overfish one of them , they will not fill again from elsewhere in the creation . ”
