Ancient bird voice box produced goose-like honks
Fossilised remains of a 66-million-year-old bird, discovered on the Antarctic Peninsula, yield its voice box – and clues to avian evolution. Anthea Batsakis reports.
The owner of the oldest fossilised bird voice box discovered probably honked like a goose as it lived alongside dinosaurs, according to a new study in Nature.
Julia Clarke from the University of Texas in the US and colleagues from the US, Argentina and China “extracted” the structure using 3-D X-ray imaging.
They suggest that birds’ sophisticated language evolved relatively late on the avian timeline, well after flight and feathers,
The fossilised voice box – also called a syrinx – was discovered in the partial skeleton of a Vegavis bird fossil on the Antarctic Peninsula.
The fossil is between 66 and 69 million years old, placing it in the Late Cretaceous block of Earth’s timeline.
Unique to birds, the syrinx is what gives them their distinctive vocal symphony.
Unlike the larynx – the voice box on top of the windpipe we use when we talk – the syrinx sits close to the heart.
It’s also double-barrelled, with each side able to be controlled independently.
But since syrinx fossils are rarely found, particularly those from as far back as the dinosaur era, syrinx evolution is still somewhat a mystery.
This is because soft tissue anatomy decays quickly and doesn’t have a chance to fossilise, unlike the more durable parts of the body such as teeth.
But, on occasion, soft tissue is preserved.
Sydney's Australian Museum’s Jacqueline Nguyen says the Vegavis discovery opens new avenues to uncover the early evolution of bird social behaviour.
“We know very little about their vocal system just because of the lack of fossils,” she says.
“A lot of studies have concentrated on the evolution of flight in dinosaurs to early birds to modern birds, but knowing that it’s possible to get fossils of syrinx preserved – it’s mind-blowing.”
In the study, Clarke and her crew propose the syrinx evolved well after flight and feathers.
If this is true, the syrinx could be what triggered the widespread bird diversification that we see today.
And by comparing it to younger syrinx fossils and to 12 living birds, the scientists pinpointed where it sat on the avian evolutionary tree.
They found its shape to be consistent with a simple honk sound, as more complex sounds would have taken longer to evolve.
“We’re often limited to work with what we have and they’ve done an excellent job using the latest technologies to get as much information as they can from the fossils,” Nguyen says.