"We described four new genera, Dione, Minerva, Clymene and Lysithea," she said.
It clarified the genetic relationships between different types of seaweed.
"In the past, people have tried to cross species that we now know belong to different genera," Dr Nelson said.
Seaweed has been harvested for food in China from at least 550AD and in Japan as early as 1000AD.
New Zealand has around 850 native seaweeds, a third of which are endemic.
Maori traditionally use species of red and green seaweed as food and customary harvest of some seaweed species by Maori has continued and is recognised in legislation.