Roughly three million years ago, imposing birds with five-foot wingspans and powerful hooked bills soared through the air and scavenged bloody seal carcasses in New Zealand, according to research published last month in the journal Taxonomy.
In the paper, scientists describe for the first time the newly discovered species of a now-extinct giant petrel, which they’ve named Macronectes tinae. They identified the bird—the only recorded species of giant petrel to have gone extinct—by studying a skull and an upper wing bone discovered on New Zealand’s North Island.
Hobbyist fossil hunter Alistair Johnson discovered the skull in 2017, followed by the upper wing bone in 2019. He stumbled upon both specimens while scouring the beaches of Taranaki, a region on the west coast of North Island situated next to the Tasman Sea. The bird’s name, M. tinae, is a nod to Johnson’s partner, Tina King, who died three years ago.
“She was pretty pleased about having it named after her,” says Johnson to the Taranaki Daily News’ Catherine Groenestein.
Though scientists don’t know for sure, because of the limited number of fossilized bones they have to go on, they suspect M. tinae was slightly smaller than its present-day relatives. The Southern giant petrel and the Northern giant petrel—two species that live in the Southern Hemisphere today—can have wingspans of more than six feet, which is about a foot longer than M. tinae’s estimated wingspan.
That makes sense to researchers, as most living species of petrels are a little bit smaller than ducks, and the two giant species are outliers. The discovery of a more diminutive giant petrel species, then, suggests the birds have been evolving to become larger and larger over time.
In addition to their size, two other characteristics that set giant petrels apart are their large, webbed feet and sturdy legs. These anatomic advantages allow them to more easily walk around on land and feast on carcasses. Other petrels, meanwhile, typically must hunt while flying or swimming in the ocean.
Scientists suspect that, just like today’s giant petrels, M. tinae was an opportunistic feeder that wasn’t afraid to get a little dirty in the process. It likely used its sharp, hooked bill to rip off pieces of flesh from carrion.
“They will not hesitate to put their entire face inside the seal and eat,” says Daniel Ksepka, a paleontologist at Connecticut’s Bruce Museum who was not involved in the project, to Live Science’s Ethan Freedman.
The researchers also posit that M. tinae had darker feathers than its modern counterparts because, during the Pliocene Epoch when the birds lived, temperatures were warmer than they are today. Scientists believe there is a link between petrel feather color and temperature.
In his 15 years as an amateur fossil hunter, Johnson has discovered dozens of specimens that shed new light on the region’s history and biology. In 2018, for example, Johnson and his son discovered the complete skeleton of an ancient crested penguin, a newly identified species that helps explain how New Zealand became a “globally significant hotspot for seabird diversity,” according to the 2020 paper describing the bird.
And this petrel discovery likely won’t be the last time that fossilized remains found on Taranaki beaches will help deepen scientists’ understanding of Earth’s biodiversity. The area, known as the Tangahoe Formation, is becoming “an important piece of the puzzle to understand the evolution and biogeography of seabirds in New Zealand and beyond,” the scientists write in the paper.