Origins of Extinct Adzebill Traced to Africa
Scientists at the University of Adelaide have revealed the African origins of New Zealand’s most mysterious giant flightless bird – the now extinct adzebill – showing that some of its closest living relatives are the pint-sized flufftails from Madagascar and Africa.
The research, published in the journal Diversity, showed that among the closest living relatives of the New Zealand adzebills – which weighed up to 19kg – are the tiny flufftails, which can weigh as little as 25g. The closeness of the relationship strongly suggests that the ancestors of the adzebills flew to New Zealand after it became physically isolated from other land.
This finding mirrors the close relationship between New Zealand’s kiwi and the extinct Madagascan elephant birds, published by University of Adelaide researchers in 2014, hinting at an unappreciated biological connection between Madagascar and New Zealand.
Like the better-known moa, the two species of adzebill – the North Island adzebill and South Island adzebill – disappeared following the arrival of early Māori in New Zealand, who hunted them and cleared their forest habitats. Unlike the moa, adzebills were predators and not herbivores.
“The adzebill were almost completely wingless and had an enormous reinforced skull and beak, almost like an axe, which is where they got their English name,” lead author at the University of Adelaide Alexander Boast says.
“If they hadn’t gone extinct, they would be among the largest living birds.”
A team of researchers from Australia, New Zealand, and the US analysed genetic data from the two adzebill species.
“A lot of past genetic research and publicity has focused on the moa, which we know were distant relatives of the ostrich, emu, and cassowary,” co-author Dr Kieren Mitchell says.
“But no one had analysed the genetics of the adzebill, despite a lot of debate about exactly what they were and where they came from.”
“We know that adzebills have been in New Zealand for a relatively long time, since we previously discovered a 19 million-year-old adzebill fossil on the South Island,” says co-author, associate Professor Trevor Worthy, a palaeontologist at Flinders University.
Original article by University of Adelaide, Science Daily, February 21, 2019.
Photo by Canterbury Museum.