The melting ice in Antarctica is leading to the discovery of previously unknown marine animals. A new species of dragonfish has been found in the waters of the western Antarctic Peninsula.
Researchers from the Virginia Institute of Marine Science (VIMS) identified the new species, named Akarotaxis gouldae. This species diverged from another approximately 780,000 years ago. The discovery highlights both the unknown biodiversity and the fragile state of the Antarctic ecosystem.
Initially, larval specimens collected off the Antarctic coast were thought to be Akarotaxis nudiceps, a closely related dragonfish. However, genetic analysis revealed significant variations in mitochondrial gene regions, leading to the conclusion that it was a new species.
Using DNA evidence, a team led by Andrew Corso examined adult samples of Akarotaxis gouldae from various ichthyology collections worldwide. Morphological differences became evident when comparing adult samples.
"There are two distinct bands on the sides of adult Akarotaxis gouldae that are not present in Akarotaxis nudiceps, so we were surprised that the species already existed in collections but had previously been overlooked," Corso explained.
Genetic testing also provided evolutionary clues. Corso and Thomas Desvignes estimated that Akarotaxis gouldae diverged as a separate species about 780,000 years ago. During this time, most of the Southern Ocean was covered in glaciers.
Scientists believe that a population of dragonfish may have been isolated within deep trenches under the 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.
Antarctic dragonfish are not well-known because they live in the remote Southern Ocean and spend most of their adult lives in deep waters. They protect their nests in shallower waters, and their young remain near the surface during their larval stage.
Examination of female ovaries showed limited reproductive capacity. Analysis of larval sampling data suggests that the distribution of Akarotaxis gouldae is limited to the waters surrounding the western Antarctic Peninsula.
"This limited distribution combined with its low reproductive capacity and the presence of early life stages in shallower waters suggest that it is a vulnerable species that could be affected by krill fishing."