3D-printed fish fossil may unveil origin of human teeth

Scientists have created 3D prints of a 400 million-year-old fish fossil found in Australia which could unveil how human teeth evolved.

Researchers from The Australian National University (ANU) and Queensland Museum digitally dissected the jaws of a fossil Buchanosteus - an armoured fish from the extinct placoderm group - and used the 3D prints to learn how the jaws moved and whether the fish had teeth.

The study helped determine when and how teeth - a characteristic feature of all animal species with jaws, including humans - had originated in evolutionary history, said Gavin Young from ANU.

"We have used CT scanning facilities to investigate the internal structure of very fragile fossil skulls and braincases that have been acid-etched from limestone rock," said Young.

"We are conducting further research on the internal tissue structure of tooth-like denticles in the mouth of the fish fossil, to determine whether they represent a transitional stage in the evolution of teeth," Young said.

The evolutionary origin of teeth was a major scientific question, said Yuzhi Hu, a PhD candidate at ANU.

"We are researching this question using new evidence from an exceptionally preserved fossil fish about 400 million years old," said Hu.

"It's great that we are able to use recent technology, such as micro-CT scanning and 3D printing, to examine some of the earliest known evidence of tooth-like structures in the most primitive jawed fishes," said Carole Burrow from Queensland Museum.

"Placoderms have been a common focus in the question of tooth origins," said Burrow.

"Our team has been able to examine the gnathal plates of placoderms from the Early Devonian period, and compare their internal and external structure with those of younger placoderms as well as with the true teeth in other jawed fishes," she said.

The findings disputed results of a previous research which suggested that the extinct placoderms had real teeth.

The new study was published in the journal Biology Letters.