New Antarctic dragonfish species discovered in Southern Ocean

A team of US scientists has discovered a new species of dragonfish, which is confined to a very small area in Antarctica.

The Banded Dragonfish (Akarotaxis gouldae), dwells in the waters off the coast of the western Antarctic Peninsula.

The dragonfish is described in a paper in Zootaxa.

The researchers found the new species by analysing the DNA of larval dragonfish collected in Antarctica, initially thought to be the known species Akarotaxis nudiceps.

They found large genetic differences, significant enough that they qualified for a new species.

“In the world of fish taxonomy, it’s becoming common to distinguish species with genetics alone,” says lead author Andrew Corso, a PhD candidate at the College of William & Mary’s Virginia Institute of Marine Science (VIMS), USA.

The researchers then examined adult Antarctic dragonfish specimens from museums around the world, finding some clear morphological differences between Akarotaxis nudiceps and the new species.

“There are two distinct bands on the sides of adult Akarotaxis gouldae that are not present on Akarotaxis nudiceps, so we were surprised that the species already existed in collections but had been previously overlooked,” says Corso.

A technique called “time-calibrated phylogeny” allowed the researchers to estimate how long ago gouldae diverged from nudiceps.

“This process essentially looks at the rate of genetic mutations as a guide for a species’ evolutionary history,” says Corso.

They calculated that the species diverged about 780,000 years ago.

“We hypothesise that a population of dragonfishes may have become isolated within deep trenches under glaciers, surviving on food pushed in by the moving ice. Once the glaciers retreated, this subpopulation had become distinct enough to be reproductively incompatible with Akarotaxis nudiceps,” says Corso.

The team named the new species after the recently retired US Antarctic research vessel, Laurence M. Gould, which collected the new dragonfish species.

This ship was itself named after Antarctic expeditioner Laurence McKinley Gould, but the researchers emphasise that they are honouring the ship.

“For several decades this vessel has supported Antarctic Science and exploration,” write the researchers in their paper.

While Akarotaxis nudiceps are widely distributed, the new gouldae species has only been found around the western Antarctic Peninsula.

“Akarotaxis gouldae appear to have one of the smallest ranges of any fish endemic to the Southern Ocean,” says Corso.

“This limited range combined with their low reproductive capacity and the presence of early life stages in shallower waters suggest that this is a vulnerable species that could be impacted by the krill fishery.”