Canterbury Museum
Right side of the tropicbird skull found in north Canterbury
A rare tropicbird fossil discovery in north Canterbury has potentially turned the historical record on its head, by suggesting the ancient species originated in Zealandia and not the Northern Hemisphere.
Palaeontologists from the University of Canterbury have discovered a remarkably intact fossil of one of the earliest ancestors of the tropicbirds group, now restricted to three species living in the tropics.
Tropicbirds are highly aerial, plunge-diving and predominantly fish-eating birds that used to live in tropical and subtropical seas.
The fossil that has challenged scientists’ understanding of the origin of the tropicbirds was found by well known amateur fossil hunter Leigh Love at the Waipara Greensand fossil site in north Canterbury, in late 2020 and early 2021. His son David helped him retrieve it.
“He was 10-years-old at the time and very keen to join me on some of my fossil hunting trips into the Waipara,” Love said.
“On this occasion when we found the bones, he said he was both surprised and amazed that we had found a flying bird.
“For me, it has been great watching a child’s face light up as a result of finding rare creatures preserved from our distant past.”
Canterbury Museum
The wing of the tropicbird fossil
Love has found other important fossils at the site, including those of a previously unknown monster penguin.
The tropicbird fossil Love found had a nearly complete skull, wing, and pelvis, and was estimated to be about 62 million years old
Named the Zealandian Tropicbird, or Clymenoptilon novaezealandicum, it was the most ancient tropicbird species ever described, University of Canterbury said.
It had features that distinguished it from all other known fossil tropicbirds, indicating it was an ancestral form of tropicbird, and suggesting tropicbirds may have originated in the seas around Zealandia, rather than the Northern Hemisphere – as previously thought.
“Features of the skull, wing, and pelvis suggest it had different feeding/foraging habits from living and other extinct tropicbirds, but because the specimen has no legs, it is not possible to get a complete picture of its mode of life,” the university said.
Leigh Love
Leigh Love’s then 10-year-old son, David, helping to collect the specimen
Fragmentary remains of what were thought to be a tropicbird were previously found at the Waipara Greensand site in 2016.
In contrast to that find, a paper on the latest findings said the newer fossil was a well-preserved partial skeleton, and was distinctly larger than the 2016 fossil.
The range of fossils found at the site, which include a primitive bony-toothed bird, and multiple species of penguin, indicated Zealandian shores were a hub for seabird diversification following the mass extinction event that caused the extinction of the dinosaurs 66m years ago, University of Canterbury said.
University research assistant Vanesa de Pietri said the extinction of dinosaurs and other land and aquatic vertebrates 66m years ago, had left vacant a vast array of habitats that birds were able to conquer.
SUPPLIED/CANTERBURY MUSEUM
A new species of giant penguin, about 1.6 metres tall, was previously identified from fossils found in Waipara, North Canterbury (file pic)
“Through all these bird fossils we are finding in the Waipara Greensand, many as old as 62.5m years old, we know that Zealandian shores played a key role in the early evolutionary history of many seabirds.
“Worldwide, the fossil record of birds this age is poor, which makes these Canterbury finds so significant in understanding what was happening with birds during the first 5m years following the extinction of the dinosaurs.”
Canterbury Museum senior curator natural history Paul Scofield said the Waipara Greensand continued to produce remarkable fossils from the early stages of the evolution of modern birds.
“This latest find demonstrates that groups of birds once thought to have evolved in the Northern Hemisphere probably evolved in the seas around Zealandia
“The nearest relatives of our new species are found in the deserts of Morocco, demonstrating that tropicbirds were a widespread group between 60 and 40m years ago.”
