The Australasian narrow-nosed spookfish - scientific name Harriotta avia - was believed to be part of a "single globally distributed species", but NIWA scientist Dr Brit Finucci says it is actually "genetically and morphologically different to its cousins".
Ghost sharks - also known as chimaeras - are closely related to sharks and rays, with skeletons made of cartilage. Unlike most fish, they do not have scales.
She named the species, discovered in the Chatham Rise off the eastern coast, after her grandmother.
"Avia means grandmother in Latin; I wanted to give this nod to her because she proudly supported me through my career as a scientist.
"Chimaeras are also rather ancient relatives - the grandmas and grandpas - of fish and I thought the name was well suited."
They are "largely confined to the ocean floor, living in depths of up to 2600m", Finucci said.
"Their habitat makes them hard to study and monitor, meaning we don't know a lot about their biology or threat status, but it makes discoveries like this even more exciting."
They feed off crustaceans such as shrimp and molluscs, Finucci said.
"Harriotta avia is unique due to its elongated, narrow and depressed snout; long, slender trunk; large eyes; and very long, broad pectoral fins. It is a lovely chocolate brown colour."
The full research paper outlining the discovery was published in the journal Environmental Biology of Fishes.
