The fossils were 19 million years old, 16 centimetres long, and in 2008 had been prised from a riverbank near St Bathans in Central Otago—the largest individual fossils recovered from the site since excavations began in 2001.
Earlier this year, Mather took them out of the bag one by one, and laid them on the bench alongside the other eagle and hawk bones she was studying.
“Straight away I thought, it’s a big bird—but it’s not an eagle,” she says. The lower ends of the bones were missing a feature that all eagles have, and she had just spent a year training herself to spot a raptor bone at a glance, “so I could see right away that it was something else, but I had no idea what.”
She showed her supervisor at Flinders, Trevor Worthy. They were both stumped. Maybe an adzebill, they thought? Worthy, a New Zealand palaeontologist known as ‘Mr Moa’ for his pioneering research on extinct birds, took the bones away for a closer look.
“He came back a few days later and said, ‘It’s a parrot’,” says Mather. “It took us all by surprise. We really weren’t expecting a giant parrot.”
The new species was described by Worthy and co-authors from the University of New South Wales and Canterbury Museum in Biology Letters this week. They named it Heracles inexpectatus after the muscled Greek hero and the unexpected nature of the find.
Worthy suspects Heracles is a super-sized member of the family of New Zealand parrots that includes the present-day kākāpō, kākā, and kea. At nearly a metre high and up to seven kilograms, it weighed twice as much as a kākāpō—which has been knocked off its perch as the heaviest known parrot.
“It’s exciting—something that’s quite unique,” says Jamie Wood, an extinct-bird researcher at Manaaki Whenua Landcare Research in Christchurch, who was not involved in the study.
“Every fossil parrot that’s been found so far is smaller than a kākāpō, yet this was twice the size. It’s just another fascinating insight that the St Bathans fauna has given us. It seems like everything that comes out of there is a surprise, and rewrites a bit of what we know about New Zealand’s past.”
Aotearoa has long been known as the epitome of ‘island gigantism’ in birds—the phenomenon where animals isolated on islands evolve over time to an abnormally large size. But most islands have just one or two bird behemoths. New Zealand has—or had—nine species of moa, two giant swans, two giant geese, giant rails, human-sized penguins, the world’s largest harrier and largest eagle.
Now we know that we had the largest parrot, too—or, at least, an ex-parrot.